Search This Blog

Monday, February 27, 2017

Zoo Review: San Diego Zoo, Part II

Today we continue the exploration of the World Famous San Diego Zoo, begun yesterday.

One of the first exhibit areas that many guests encounter are the reptiles.  Most zoos have a reptile house - San Diego has one too.  It also has an entire reptile region.  Walking around the perimeter of the open-air Reptile House, visitors can observe a variety of species, from the familiar - Komodo dragon, Indian cobra - to the more elusive, such as Kaiser newts and Ethiopian mountain vipers.  The Reptile House is actually one of three here at the zoo - there are two others nearby, one featuring native Californian species (I was especially impressed with the horned lizards), another displaying amphibians of the world.  Scattered around the three buildings are outdoor enclosures of larger reptiles (well, not all of them larger than the Komodos) such as Galapagos tortoises, Burmese mountain tortoises, and Cuban iguanas.  A series of crocodilian pools frames out the trail, including Chinese alligators and slender-snout crocodiles.


Near the reptiles is the Children's Zoo, home to a petting barn area, an insect house, and habitats for several small mammals, such as naked mole rats, North American porcupine, and fennec foxes.  Animal encounters abound here - it was here that I was able to see a living pangolin for the first time, though that individual has, sadly, since passed.  There are also playgrounds and a 4D theater.  More animal presentations can be seen nearby in the Wegeforth Bowl.

About half of the zoo grounds are taken up by The Lost Forest, a massive complex of intertwining paths snaking through dense vegetation that features animals of the rainforests.  The entryway lies near the zoo's entrance, passing between two of the zoo's most memorable sights - a raucous flock of nesting flamingos and an enormous, towering Ficus tree, as much a landmark of the zoo as many of the animals that live here.  It's easy to get lost on these winding trails, as they split and regroup unexpectedly.  In part, this occurs when one path goes to follow a ground-level route, while the other takes to the canopy to observe birds and primates among the branches.  This is the heart of the zoo's primate collection, and mandrills, guenons, and capuchins can be seen along the trail.  Non-primates include duikers, Visayan warty pigs, and pygmy hippos, the later sharing their home with cheeky Wolf's guenons who aren't above hitching a ride on the hippos' backs.  The largest primate exhibits are for the great apes.  Gorillas and bonobos (also called "pygmy chimpanzees") can be found on the trails; elsewhere, Sumatran orangutans share a towering climbing structure with a family of siamangs.


I mentioned that it's easy to get lost, but no matter which way you go on these trails, you'll find something.  In my case, I wandered down a side-trail that turned into Tiger River, home to many of Southeast Asia's most spectacular creatures.  Along the water course, I encountered fishing cats peering from within hollow logs, a Malayan tapir splashing in a pool, and gharials bobbing in the water, watching visitors eye-to-eye.  Several bird exhibits also lined the path, including one massive aviary that held rarely-seen Storm's storks.  Another seldom-seen exhibit animal: giant coconut crabs!  It was the tigers that held the attention of most visitors, however, and the big striped cats live in a densely planted yard with a waterfall-fed pool. 


Asia gives way to Africa as the trail leaves the tigers and enters Ituri Forest, featuring animals of the Congo.  Okapi are the first animals that visitors meet, with the path then turning into a overlook of a pool of hippos.  The hippos are visible from underwater viewing windows; they can be a little hard to spot sometimes through the crowds of fish, but as soon as they approach the window, be prepared to be engulfed in an enormous, camera-happy crowd.  Down the path from the hippos is one of the coolest mixed-species exhibits I've ever seen.  African buffalo (of the red forest subspecies) chew their cuds placidly while monkeys and spot-necked otters frolic about.  A bridge cuts through the exhibit, with the buffalo confined to one portion, the monkeys and otters having access to both sides.  Among the primates are Allen's swamp monkeys, which sometimes join the otters in the pool and swim past the underwater windows.  The trail empties out at the bottom of the zoo, near pools patrolled by pelicans and saddle-billed storks.


Scattered among the rainforest exhibits are three walk-through aviaries, ranging from big to gigantic.  Scripps Aviary houses African birds, Owens Aviary featured Australasian ones, and the smaller Parker Aviary has South American species.  Between them are smaller exhibits for other birds, including the zoo's astonishing collection of birds-of-paradise.

Too tired to make your way back to the entrance?  The zoo is willing to give you a lift... literally.  A Skyfari tram sweeps visitors across the zoo, providing panoramic views of the park.  An even more beautiful view of the zoo - and one far less traveled - is in the lushly planted Fern Valley, a winding pathway through a jungle of vegetation.  It can be somewhat steep and there are no animals, so visitors don't wander here as much, but that makes it all the more soothing and peaceful after a hectic day of exploring the zoo.


As if San Diego Zoo didn't have enough to boast about, it's about to get even bigger.  As a 100-Year Birthday gift to itself, the zoo is preparing to unveil Africa Rocks, an exhibit area larger than many zoos.  Among its occupants, visitors will find African penguins (currently in temporary quarters in the Children's Zoo), leopards, red ruffed lemurs, hamadryas baboons, and honey badgers, among other species. 

What more can be said about the zoo?  It's extraordinary.  If it has a weakness, it's its own success.  The zoo is so popular that even with its tremendous size, it can get very crowded, which makes it difficult to have the intimate moments with animals that you can experience at smaller zoos.  In the case of its larger mammal residents, it's hard not to draw unfavorable comparisons with the San Diego Zoo Safari Park, located just to the north in Escondido.  There's nothing wrong with the Zoo's exhibits... but if you're going to do both, I would definitely come here first.  After seeing rhinos, giraffes, and other large mammals in sweeping vistas, the somewhat conventional exhibits here may seem somewhat of a let-down. 


When all is said and done, there is nothing to say about the zoo - both the grounds and animals and its place in the world - other than "excellent."  San Diego Zoo Global (the combination of the zoo, the park, and their conservation programs around the globe) is one of the most prominent zoos on earth working to beat back the sixth extinction.  They've been involved in numerous projects around the world, ranging from spear-heading captive-breeding and reintroduction programs (their work with Hawaiian birds has been especially impressive) to restoring habitats to researching ways to lessen human-animal conflict around the globe.  I find their commitment to their own staff to be especially impressive in the fields of employee mentoring, wellbeing, and professional growth.

As San Diego Zoo turns 101 this year, its staff can take pride in knowing that they've fulfilled Harry Wegeworth's dream of creating a world-class zoo that is a leading light for wildlife conservation.

Sunday, February 26, 2017

Zoo Review: San Diego Zoo

There are a lot of zoos in the world.  There is only way that is seldom named without the introduction of "World Famous..."

It began, they like to say, with a roar.  In 1916, San Diego physician Dr, Harry M. Wegeworth was driving along the edge of Balboa Park on September day in 1916.  Whatever thoughts were going through his head at that time, they were shattered by an unexpected sound - the roaring of a lion.  The park had been the site of the recent Panama-California Exposition, meant to celebrate the opening of the Panama Canal.  A variety of animals had been exhibited there, some of which had been abandoned.


Wegeworth turned to his brother, riding in the car with him, and commented, "Wouldn't it be splendid if San Diego had a zoo?  You know... I think I'll start one."

Just over 100 years later, the San Diego Zoo stands out as perhaps the most famous zoo in the world.  Built in the immediate aftermath of the Hagenbeck revolution of zoo design, it was one of the first zoos to pioneer open-air, natural enclosures from its very beginning.  The region's stunning climate allows vegetation from around the world to thrive on zoo grounds, leading to some of the lushest, most well-planted exhibits anywhere (while also providing excellent browsing for herbivorous animals).  That same climate also allows many animals to be exhibited outdoors year round instead of being cooped-up in winter holding barns.  Now located in Balboa Park, the site of the zoo's unanticipated origin, the San Diego Zoo has fulfilled Dr. Harry's (as the staff still refer to him as) dream of a world-class zoo famed around the world.


San Diego has an extraordinary collection, but if there is one animal for which the zoo is best known, it is the koala.  For many years San Diego was the only zoo in the United States to exhibit koalas; joeys produced here have since populated zoos around the country.  To this day, it features the largest collection of koalas outside of Australia.  The marsupials are the stars of the Outback area, nicknamed Koalifornia.  For all of their fame, koalas don't do too much (essentially, they are marsupial sloths), and the koala exhibits (there are several) are basically a row of trees, each with a koala sleeping in it.  Less sought-after but more active exhibits nearby include wallabies, wombats, and Tasmanian devils.  Also found here are several aviaries of gorgeous Australian birds.  Side complaint: San Diego has one of the best bird collections in the world... which made it all the more frustrating to me how hard it was to see any of them clearly, let alone photograph them, through the heavy mesh that their aviaries are built out of.   Hopefully, the zoo will begin the process of switching them out with finer, less visible materials at some point. 

Near the koala building is the zoo's Urban Jungle region, home to some of the most recognizable zoo animals - giraffes, red kangaroos, and Indian rhinoceroses, to name a few.  This is also the permanent home of some of the zoo's animal ambassadors, which are used for meet-and-greets with visitors.  Among the most popular of these are the ambassador cheetahs.  When not out for walks, the cheetahs can be found sprawled out in a grassy yard, sometimes in the company of their companion dogs; signage nearby emphasizes that the dogs are friends, not food, for the spotted sprinters.

Koalas are often erroneously referred to as bears, but the real bears are near by.  Andean bears from South America and grizzly bears from North America inhabit rocky grottos near the zoo's entrance.  These are some of the only original exhibits of the zoo, as much of the rest of the facility is constantly being renovated.  While hardly spectacular compared to many of the newer exhibits, they are still excellent compared to the bear exhibits of many zoos, with rockwork, pools, and even vegetation (how on earth do you keep plants alive in a bear exhibit?  Inquiring minds want to know!).  A third bear species is found further down the trail in Sun Bear Forest with endangered Asian primates - gibbons and lion-tailed macaques - in nearby exhibits.


Yet another bear species is found in Polar Bear Plunge, the big white Arctic bears being perhaps one of the least-expected residents of sunny San Diego.  Don't feel too bad for the bears in the heat, however - they have a vast pool to swim and dive in, with visitors watching them from an underwater viewing gallery.   Caribou occupy a rocky hillside enclosure nearby, while an Arctic marsh aviary is filled with beautiful diving ducks and other birds (also viewable underwater).  What I really enjoyed and appreciated about Polar Bear Plunge, however, was its willingness to explain and explore the leading threat to the animals of display - global climate change.  The phenomena - and what we can do to address it - was highlighted in several fun, easy to understand graphics that encourage interactive learning. 

The zoo's final bears are the only species in the zoo which could challenge the koalas for the title of "Most Popular Zoo Animal."  San Diego is the only zoo in the country to exhibit koalas AND giant pandas, which are on display in Panda Trek.  The line to see the black-and-white bears can be tediously long, all for an animal which, again I'm biased here, doesn't do too much (if I live to be 100, I'll never understand the hype about pandas over all other species).  I was much more interested by the other animals seen along the way - red pandas, for instance (the more engaging of the pandas), or takin, clambering across a boulder-strewn yard, for instance, or beautiful-but-venomous Mangshan vipers, a species that wasn't even known to science when the zoo was founded.   Snow leopards and Amur leopards occupy a series of enclosures on either side of the visitor pathway; the spotted cats can pass from one to the other through a set of overhead passageways, traveling directly above zoo visitors.


Either the pandas or the koalas may be the biggest stars of the zoo.  The biggest animals period are the residents of Elephant Odyssey.  The zoo bills this exhibit as a time-travel back to the California of the Pleistocene, when the Golden State was filled with wondrous beasts, many of which have since vanished.  Besides native Californians, the trail also features the living-descendants (or close approximates) of the animals that once lived here.  You can encounter pronghorn "antelope" in a desert yard, for instance... which they share with camels.  Or see jaguars, which lived in California until quite recently, historically speaking... and next door are the lions, found here prehistorically.  Other occupants of the trail are rattlesnakes, wild horses, sloths, and secretarybirds, as well as a mixed species habitat of guanaco, capybara, and Baird's tapir, the later two often found lounging in their pool.    The Asian elephants here are stand-ins for mammoths and mastodons, and occupy a sprawling yard with pools, shade-structures, and hanging feeders that encourage them to reach up high for food.  Their barn is nearby; unlike many zoo elephant barns, this one is completely on-display, giving visitors a behind-the-scenes peek in how elephants are cared for.  Also on display are California condors, a highly endangered species that was saved from the brink of extinction in large part due to the efforts of the zoo's sister-facility, the San Diego Zoo Safari Park. Connections to California's past are highlighted with life-sized statues of mammoths, giant ground sloths, and other Pleistocene beasts; a recreation tar pit furthers the experience, and docents are often on-hand with replica fossils.


Scattered among these regions are exhibits for pumas, maned wolves, zebras, peccary, and various antelope, as well as a series of towering aviaries for massive birds of prey - harpy eagles, Steller's sea eagles, and Andean condors among them.

Well, it took me more than one day to cover the zoo, so it'll have to take a second blog post to the cover the zoo and do it any justice.  More details on exploring San Diego Zoo tomorrow!


Saturday, February 25, 2017

The Monsters in the Menagerie

I was originally going to title this post, "Welcome to the Freak Show."  I opted not to, in the end, out of a case of sensitivity.  The term, attached to circuses and carnivals throughout the centuries, has always carried with it the stigma of degradation.  Persons born with disabilities and deformities were collected - sometimes willingly, other times not - for display, for the education and amusement of anyone who could pay.  The more striking the deformity, the more popular the attraction.

The same could be said for animals.  Just as many rulers throughout the ages kept menageries, many also kept collections of deformed or unusual people.  The Spanish conquistadors, for example, found an entire section of Montezuma's royal zoo devoted to this purpose.  Perhaps the best known human exhibit was John Merrick, known popularly as "The Elephant Man."  Merrick himself mused that his physical appearance may have been due to his mother being frightened by a menagerie elephant while she was pregnant with him.

Of course, if people were willing to pay to see exotic animals, and people were willing to pay to see deformed humans, you can bet that they were willing to pay to see deformed animals.  Every carnival or fair that could find one would have a chicken with three legs, or hermaphroditic pigs, or a calf with two faces.  If the creature was too maladapted to survive outside its mother's womb, than you could be sure that it would be there in a jar, drifting in formaldehyde.  If a genuine "freak" couldn't be found, one could be produced, as evidenced by the countless monkey carcasses that found themselves grafted with fish tails and presented as "Mermaids."

Such animal curiosities seldom appear in modern zoo collections.  For the most part, a zoo is not considered a profitable venue for the owners of such oddities to sell their creatures.  Most zoos themselves have little interest in such creatures either, preferring to display animals that resemble the natural state, rather than medical abnormalities.  The exception to the rule?  Color morphs.  Zoo and aquarium staff have long had a weakness for abnormally colored animals.  Snowflake the albino gorilla was the star of the Barcelona Zoo for years.  Black panthers are exceedingly more popular than spotted leopards or jaguars.  The white alligators of Audubon Zoo and Audubon Aquarium have become legendary.  And, of course, the most famous zoo oddities of all - white tigers. 

I'm not sure what the rational behind this is.  I suppose it comes down to logistics and aesthetics.  Many physically malformed animals have a hard time surviving, which is part of the reason that they are so seldom encountered (besides the fact that they rarely occur at all).  Apart from their sensitivity to sunlight in some instances, color morphs pose few challenges compared to their normal colored-counterparts.  Also, whereas many visitors find animals with extra (or too few) limbs, eyes, etc to be off-putting or pitiful, white tigers and albino alligators are often seen as beautiful and special.

I will admit, I've also seen a few two-headed reptiles in a few collections.  I've never really enjoyed seeing animal oddities (apart, I'll admit, from color morphs), having felt that they're too much focus on sensationalism and drama, too little contribution to the zoos' serious goals of conservation and education.  In this I feel they resemble hybrids, though the latter are often deliberately produced.

I suppose it's worth noting, however that for people who aren't familiar with animals, there isn't much of a difference between an exotic animal they've never heard of before, one that is the hybrid of two other species, and one that is exhibiting some sort of abnormality.  What they know about the animal is entirely up to the displaying institution's messaging.

Wednesday, February 22, 2017

Sporcle Quiz: Hybrid Animals


I'd always known that there were a lot of strange hybrid creatures out there, but researching yesterday's post was a reminder of just how many there truly are.  Enjoy today's quiz, featuring match-ups of some of the common and uncommon hybrid animals.

Tuesday, February 21, 2017

Hybrid Vigor

What do you get if you cross an octopus with a spider monkey?  A loss of funding, a PETA protest, and a very stern letter from the university's genetics department.

What do you get if you cross a giraffe with a zebra?  An okapi, apparently.  A cat with a bear?  That gets you a binturong.  What about a pig with an elephant?  That's where tapirs come from.

None of this is remotely true, of course, but they are all things that I've heard from visitors before.  Show people an unfamiliar animal, and they will instantly liken it to something familiar, saying that it looks like a cross between an A and a B.  I think some guests think that there are only a few dozen species of animal in the world, and that the diversity of life that we see is the result of endlessly cross-breeding and mixing them.  Of course, this belief goes back to ancient times - the earliest name of the giraffe, for instance, was Camelopard ("Camel-Leopard"), a fact which is immortalized in the species Latin name.

None of this, of course, is to say that hybrids don't happen - sometimes in the wild, far more commonly in captivity.  And few things make zookeeping more complicated than hybrids.

A hybrid can occur on one of several levels.  It can be the cross between two subspecies, such as an Amur tiger crossed with a Bengal tiger.  It can be between two species, such as a lion with a tiger.  Sometimes it can even be across genera, such as a puma crossed with leopard.  Some hybrids are sterile, such as those between horses and donkeys.  Others are fertile, such as those between brown and polar bears.

There are several reasons why people might produce a hybrid. 

Sometimes they happen by accident.  At one zoo where I worked, green tree pythons and carpet pythons shared an exhibit.  The two closely-related species bred and produced a clutch of babies which were stunningly beautiful and horrifyingly irascible (we were forbidden to take pictures of them - the curator didn't want to publicize our mistake).  Such roommate-pairings can occur in many mixed-species exhibits, with waterfowl and pheasants being notorious for hybridizing.  Often, if there are suitable partners of the correct species, animals will still choose to match with their correct mate.  While our babies were "whoopsies", some breeders breed them on purpose to create novel color patterns.

Sometimes it is done deliberately for a specific purpose  Gyrfalcons, the largest of the falcons, are prized by falconers for their ability to capture larger prey.  Being an arctic species, however, they tend to be susceptible to diseases when kept in temperate climates.  Falconers have been known to cross them with other falcon species, such as peregrines and sakers, to produce a bird that is large but disease-resistant.  Or you could look at the most famous hybrids in the world - mules and hinnies, the cross between donkeys and horses, used as work animals for millennia.

All too often, it's done just for the heck of it.  No animal exemplifies that better than the liger or its counterpart the tigon.  Crosses between lions and tigers are often larger than both and retain a slight mane (the legacy of one parent) and faint striping (from the other).  Ligers are commonly produced in private collections, maintained for their "wow" factor.  Some zoos then like to hybridize their hybrids - let's see how many of the big cats we can get in one!  Zebras crossed with domestic equines - horses and donkeys - are another commonly encountered hybrid.

A small number of hybrids occur naturally - though often humans show their hand in the mix somehow, whether by modifying the environment or by introducing species.  With the disappearance of wolves over much of North America, coyotes are filling the vacuum.  Sometimes wolves, unable to find a mate of their own species, will pair up with coyotes.  Genetic "swamping" with coyotes is one of the leading threats to the last remaining red wolves.  Similarly, endangered Cuban crocodiles increasingly find themselves mating with the American crocodiles that are encroaching on their range; ditto for spotted owls and barred owls.  Lately, polar bear/grizzly bear hybrids have been in the news, serving as another warning about global climate change.

From the perspective of a reputable zoo, it's hard to see any value in hybrids.  Our goal should be to showcase and conserve animals as they are, not as we imagine they might be, and certainly not just tampering with gene pools for a giggle.  This is especially true in the face of future reintroductions.  A hybrid between two species is often less well-suited to life in the wild than either of the parent species. 

Desperate times sometimes call for desperate measures, however.  For example, in Tears of the Cheetah, Stephen O'Brien recounts how, in a last-ditch effort to save the rapidly disappearing Florida panther, conservationists decided to add fresh blood to the gene pool in the form of Texas cougars, another puma subspecies.  Though controversial (some critics asked if the resultant animals could still count as Florida panthers), the decision is credited with saving the panther.

Of course it's not a hybrid's fault that it is a hybrid, and most keepers will maintain that the animal needs to be given care for the rest of its life, ideally being neutered or spayed first to keep it from contaminating a population (sorry, that sounded more eugenics-y than I intended).  Doing so is admirable animal welfare, but comes at a cost.  A hybrid animal takes up space, resources, and keeper time that could go to other animals that are far more useful for conservation purposes.  In the case of long-lived, labor-intensive species, such as orangutans (lots of Bornean-Sumatran hybrids back in the day), the commitment can be extraordinary.

Once hybrid genes are in a population, they can stay there, hidden, unless a telltale trait emerges, or if someone thinks to do genetic screening.  With hybrids, it really can be said than an ounce of prevention is worth a pound of cure... and by "a pound of cure", I mean "Twenty years of care, thousands of dollars in food and vet bills, and a perfectly good enclosure that's been held up for that animal's entire life."

One last note about hybrids.  The two species involved have to be at least somewhat related to cross-breed, though it varies how closely based on the situation.  You can cross a leopard with a jaguar, or a camel with a llama.  You cannot cross an African elephant with a gorilla, or a walrus with a kangaroo.  (Though I'm sure that out there, there's someone who'd love to try...)

Monday, February 20, 2017

Species Fact Profile: Chinese Crocodile Lizard (Shinisaurus crocodilurus)

Chinese Crocodile Lizard
Shinisaurus crocodilurus (Ahl, 1930)

Range: Southeast China, Northeast Vietnam
Habitat: Evergreen Bamboo Forests, Mountain Streams
Diet: Insects, Small Fish, Tadpoles
Social Grouping: Solitary
Reproduction: Breeding season is July and August.  2-7 young are born live after a gestation period of 8-12 months.  Young are independent at birth.  Sexually mature at 2-3 years old
Lifespan: 10 Years (Captivity)
Conservation Status: IUCN Endangered, CITES Appendix II


  • Body length up to 45 centimeters.  Most prominent features are the enlarged, bony scales on the back and tail, making the lizard resemble a crocodile
  • Upper surfaces are mottled grey and brown, turning into yellow or tan on the understand with some distinctive bright orange markings, especially on the sides, throat, and the side of the head.  Males tend to be more colorful than females, especially in the breeding season
  • Locally known as "the Lizard of Great Sleepiness" due to its ability to remain motionless for hours at a time, even underwater (it is capable to reducing its breathing rate).  This tendency towards inertia is responsible for a native belief that it can cure insomnia
  • Though primarily solitary, with one lizard usually occupying each pool, several individuals will share a winter den in a rock crevice from November through March
  • Spends most of its time on rocks and branches overhanging waterways, will take to the water quickly if disturbed
  • Habitat loss and disturbance has resulted in the drying up of pools; loss of plant cover leaves lizards more vulnerable to predators.  Also collected for the pet trade and for its role in Traditional Chinese Medicine

Saturday, February 18, 2017

Zoo History: Mapping the Family Tree

"A little more than kin and less than kind."

- William Shakespeare Hamlet, Act I, Scene II

For most of their history, zoos and aquariums were able to replenish their exhibits from the seemingly inexhaustible stores of the wild.  In the decades following the end of World War II, however, the doors to the wild began to slam shut, one by one.  Newly independent nations of Africa and Asia began imposing limits of the export of their wildlife.  New national laws and international treaties regulated the trade of species.  Public opinion began to turn against the idea of capturing wild born animals for zoo displays.  And, finally, it began to become apparent that the wild maybe wasn't as inexhaustible as it once seemed.

For zoo curators and collection managers, the choice was stark.  Either stop displaying certain species... or learn to breed your own.

Many of the more positive trends in zoo husbandry began to develop as a result of this trend.  In order to breed species, zoos began to move towards large exhibits that allowed for the expression of more natural behaviors.  Collections moved from single-specimen "stamp collections" (one white rhino, one black rhino, one Indian rhino, one Sumatran rhino...) to species-specific social groups.  Then came the realization that mental health was just as important as physical health, resulting in the adoption of more behavioral enrichment.

The work began to pay-off.  Animals began to breed.  Sometimes the babies thrived.  Other times... not so much.

In the late 1970s and early 1980s, National Zoo biologists Katherine Rawls and John Ballou began a study of the survival rates of mammals in zoos.  They started with ungulates, but also looked at small mammals, primates, and other taxa.  In each case, they made the same discovery.  The more closely the parents were related - the more inbred a young animal was - the less likely its chances of future survival.  Inbreeding led to reduced fertility and greater infant mortality.

Like many genetic developments, this seems old news now, but was pretty serious stuff back in the day.  After all, while direct incest - mother to son, brother and sister - was frowned upon in human society, a lot of royal families, such as those of Europe in the 1700s and 1800s, were basically a bunch of family trees with seriously intertwined branches.  Even among the middle class, marrying cousins was normal; heck, Charles Darwin married his.  And Cleopatra was the product of who knows how many generations on inbreeding.  And that's just people!  Look at our domestic animals, such as purebred dogs if you want to see some murky genetic issues.

The solution in this case was pretty straightforward.  Stop inbreeding.  That became the tricky part, however.  Zoo populations tend to be small ones, especially when you are dealing with very endangered species which have seen a tremendous loss in their numbers.  The Arabian Oryx World Herd, for example, started with NINE animals.  Plus, how do you keep track of how related all of these animals are?

Out of the work that Rawls and Ballou published came changes that reshaped the zoo world.  The international zoo community worked to create a registry of all the animals (as many as possible, anyway) in their collections.  The International Species Information System, or ISIS (for reasons I can't begin to imagine, they recently changed their name, opting for Species360 instead) keeps track of what animals are in what collections around the globe.  On a more specific scale, Rawls and Ballou saw their work lead to the development and adoption of the studbook program.

I saw this sign at the San Diego Zoo, and thought that it summed the concept up pretty nicely.

A studbook is essentially a biography of a population.  It keeps track of what animals, both current and historic, are born and die, where they lived, who their parents and offspring are, and how they fit into the population as a whole.  Studbook keepers (the biographers of the populations, if you will), help maintain the genetic health of the population by making sure it retains as much diversity as possible by deciding who breeds with who.

The Rawls and Ballou papers never achieved much fame or glory.  I doubt that's what they were looking for, but they deserve it nonetheless, having helped crack open one of the greatest threats to maintaining animals under human care for several generations.  Their research and insights into the dangers of inbreeding also have important consequences for the study of wild populations, especially those trapped in small and increasingly isolated patches of protected habitat.  When the first of their papers were published, biologists were worried about zoos being the "small" populations.  Today, for several species in zoos, the zoo population is getting bigger.  The wild ones, however, are getting smaller and smaller.