Tuesday, November 15, 2011

Leopard, Contained

Today I watched a leopard pace in its tiny cage.  Male leopards are used to 30 square miles of home range, and this one was lucky to have 30 square yards.  This subspecies of leopard, the Amur leopard, is critically endangered in the wild, and the zoo is participating in a conservation program that likely helps to maintain biodiversity so the species doesn't go extinct.  Nevertheless, this leopard was pacing.  There was a clear path worn in the grass, and he was bored.

Amur Leopard, Panthera pardus orientalis.
Leopards are often confused with jaguars and cheetahs, but once you look carefully at their spots, you won't confuse them again.  Leopards have hollow spots, called rosettes.  Jaguars' rosettes have little black spots inside each one.  Cheetahs have solid spots.  Leopards are the largest and stockiest of the three, with large males tipping the scales at 200 pounds, though most are smaller.

Notice the empty rosettes that indicate this is a leopard, not a jaguar.
Leopards' biggest difference from other big cats is a behavioral characteristic.  They are generalist carnivores.  They will eat anything from the size of a dung beetle to a 2000 pound male eland, as long as it is in the Animal Kingdom.  They prefer prey in the 44 pound - 175 pound range, which is a bit disconcerting for a species with most of its members in the preferred prey size range.  Leopards could take humans for prey easily - their range overlaps with humans, they are well camouflaged, and they can hide around human settlements.  For some reason, leopards don't choose to take humans - they hunt all other animals preferentially.  A few leopards that were injured or sick have taken humans as prey in the past, and once they started, they kept doing it until they were killed.

As explained in a previous post, generalist predators tend to have more intellectual capacity than predators that don't have to make as many decisions or learn about as many different types of prey.  Leopards hunt alone, which means they are unlikely to evolve complex social interactions, which is likely cold comfort to their prey.  Leopards are definitely stronger than other big cats of similar size, and they have been observed hauling prey up to three times their weight high up into trees to save for a later meal.  This combination of strength and intelligence makes the leopard particularly awe-inducing to me. 

The highlight of our leopard-watching for the day was a dangerous game between the leopard and a squirrel, two smart-cookie generalist consumers.  The squirrel had found a prized piece of hot dog bun near the leopard cage and was trying to decide whether to eat it in place or carry it away to another location, a vegetarian version of the leopard's prey-stashing.  The leopard heard the leaves rustling around the squirrel, crouched, sighted the squirrel and pounced.  The leopard was denied its afternoon snack by only a thin wire fence.  The squirrel continued to appear to frolic in the leaves, rustling them unnecessarily along the edge of the cage for another minute or two before it left to gorge on simple carbs.  The leopard was as agitated as a house cat being teased with crinkly paper.  It struck me that the squirrel had learned the fence would hold and ignored the deadly but contained predator.  The leopard had not completely habituated to the fence and continued to respond to temptations on the other side.  It either hadn't learned the fence was immutable or its brain was so exquisitely tuned to the rustling prey sounds that there was no other possible behavioral response the leopard could offer at the moment.  If you have ever played with  house cat, it certainly seems that they are compelled to pounce on rustling things - perhaps it is the same with big cats.
Leopard focused on a squirrel just two feet away.

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