Romance at the Zoo

Happy Valentine’s Day! 

It’s that time of year when everyone is expected to start thinking flowers, candy, and – above all – romance!  Unless, of course, you work in a zoo or aquarium.  If you do, everyday is Valentine’s Day, and romance is always in the air! (Along with various unique aromas and the attendant flies)…

It may not seem it at first glance, but zoos are always concerned about romance – at least among their charges.  Romance among the human occupants is something entirely different (maybe more on that in a later post…).  Long gone are the days when zoos filled their collections by placing orders with Frank Buck, Carl Hagenbeck, and other animal dealers.  To be sure, some animals in zoo collections do still come from the wild, but fewer and fewer, especially among the larger mammals.  Part of this is the difficulty in navigating the permit process and international laws.  Part of it is a reflection of the fact that there really isn’t much of a “wild” to pull animals from anymore. 

End result: in many cases, if zoos and aquariums want animals, whether for education programs, exhibition, or future reintroduction programs, they have to breed them.

So, you take a daddy animal and a mommy animal, put them in a cage together, give them a chance to know one another, and boom, you get a baby, right?  The stork (conveniently found in the exhibit next door) pops over with a bundle in its beak.  Not quite…

Come to think of it, who brings the storks' baby?

For some species, captive breeding is extremely easy.  This is true of domestic animals (they wouldn’t be domesticated if they were hard to breed).  To a lesser degree, it’s also true many of the large, popular zoo animals, such as lions, giraffes, and zebras.  I’m pretty sure that I could take a lion and lioness, keep them in the cramped spare room in my apartment, add food and water, and a few months later I’d have cubs.  For prolific species, the concern is overpopulation – if everyone bred all the time and pumped out cute babies for display, we’d quickly have a problem of those cute babies growing up and having nowhere to place them… which leads to tough decisions that we’d all rather avoid.

Other species can prove difficult to breed for a variety of reasons.  The first captive birth of a gorilla occurred in 1956, with Colo at the Columbus Zoo.  That year also saw the first captive birth of cheetahs since the days of the Moghal Empire, when Akbar the Great’s hunting cheetahs produced a litter (and to be fair, he had 1000 cheetahs… someone was bound to give birth).  The Sumatran rhino calf born at the Cincinnati Zoo in 2001 was the first captive birth in well over a century.  But why are these species harder to breed?  A lion is a cat, and a cheetah is a cat… what’s the difference?

If a species isn’t breeding in captivity, it usually means that some essential ingredient is missing from the occasion.  For clouded leopards, it turned out to be privacy.  Most zoos use to house their big cats all together in one building.  Clouded leopards turned out to be easily stressed by the presence of bigger, scarier cats in close quarters and that impaired their breeding.  Given quarters removed from the lions and tigers, with a few other changes (such as taller enclosures – they like to be up high), breeding success improved. 

For flamingos, the opposite proved true.  Flamingos in the wild breed in massive flocks of thousands upon thousands of birds, and it turns out that they are most likely to breed in large congregations.  The more flamingos a zoo has in its flock, the more likely they are to breed, with 40 appearing to be the magic number where success becomes most likely.  Can’t accommodate forty flamingos?  Don’t worry – some zoos have used strategically placed mirrors to trick flamingos into thinking they are part of a bigger flock. 

Tomato frogs take it a step further – scientists at one zoo found that females are stimulated to release eggs by the jarring of several males clambering on top of her, trying to push each other out of the way (if you only have one male, it turns out that you can recreate this affect by holding the male on top of the female and wiggling him vigorously).

In some animals, reproductive success is triggered by changes in their environment.  Many birds base their breeding seasons of changes in day length; for these species, zoos may alter the light cycle with artificial lighting.  For reptiles and amphibians, changes in temperature may be the cue that is missing – many zoos chill their reptiles prior to breeding.

In some species, the female will mate with any eligible suitor.  In some (like cheetahs), she may be choosier, and do best when she has a variety of options.  In some species, males and females stay together year round.  In others, novelty is a turn-on, and the pair should only be brought together for breeding, and then separated again.  Absence makes the heart grow fonder, and all that.

Romance at the zoo isn’t allowed to go rampant and unchecked.  Many species displayed in zoos are part of Species Survival Programs – carefully managed breeding programs where matings are planned out to maximize the genetic health and sustainability of the population.  It sounds better if you try thinking of it as Match.com for rhinos and pandas. 

At present time, there are about a dozen species at my zoo that we are attempting to breed.  They range from large carnivores to waterfowl.  Some of them will take care of themselves on their own – all I’ll need to do is keep them fed and happy.  Some might require a little coaxing – putting out nesting material, minimizing disturbances, upping their diets.  Some I’ll have to wait, either for prospective mates to be introduced peaceably (not easy with some species), in others for one partner or the other to come of age.   Any progress will be duly noted, and husbandry and routines will be changed based on the outcomes.  If there are resultant offspring, there will be more changes still.

Keeping track of it all is a job in itself.  No way that we could do it all just on one day in February.  I guess it’s a good thing that for a zookeeper, everyday is Valentine’s Day!

PS:  Want to learn more?  Many zoos host "Sex at the Zoo" (not as naughty as it sounds) programs around this time of year.  Check and see if your local zoo has one!