Milwaukee cubs take a dip in a new gene pool

The Milwaukee County Zoo is happily welcoming two new additions to its jaguar exhibit. Two unnamed cubs, born last Nov. to the zoo’s female jaguar Stella, made their debut in Feb. where they appeared alongside their mother for a few hours every day. What’s so special about these cubs, however, is not that they’re cute. Let’s face it — all baby animals are adorable. These cubs are special because of their genes. Their father, Pat, was caught in the wild in Central America before being sold to the Milwaukee County Zoo.

An image from the Jaguar Cam where viewers can watch the mother and cubs online. Image from Milwaukee Zoo.

An image from the Jaguar Cam where viewers can watch the mother and cubs online. Image from Milwaukee Zoo.

Pat’s story is a very common one in Central America, with the exception that his has a happy ending. Deforestation and urbanization threaten the jaguar’s habitat, forcing them to come into contact with humans often. Jaguars sometimes attack cattle — as Pat did — and are considered pests by farmers. Most jaguars in these situations are hunted and killed, but Pat was kept alive and sent to the Belize Zoo where he stayed until 2008 when he became an immigrant to Wisconsin.

Genetic diversity is one of the largest problems zoos face when maintaining their populations. In order to maintain diversity, you need genes from a wide range of sources, but catching wild animals to place in zoos is a fairly unpopular idea. Therefore zoos rely on each other for different animals, but after a few generations the animals all become closely related. Low populations eventually lead to inbreeding, at which point that population is in danger of being lost. That’s why Pat’s DNA (and his sons’ DNA) is so valuable.

The new cubs with mom. Image from Milwaukee Zoo.

The new cubs with mom. Image from Milwaukee Zoo.

If the problem sounds familiar, you might have heard about it in talks about cheetah populations. Cheetahs suffered from a population bottleneck — a sudden drastic reduction to their numbers — about 10,000 years ago, limiting their genetic diversity. This problem never corrected itself, and now the cheetah population is so small that every single member shares 99 percent of their genes, more or less qualifying them as clones. A healthy population is supposed to share only around 80 percent of its unique genes. Inbreeding caused by low genetic diversity is a common cause of extinction, leaving little hope for the cheetah.

Once Milwaukee’s jaguar cubs are older, they’ll be sold to other zoos in order to increase the genetic diversity there. With the new genes, zoologists hope to maintain their jaguar populations for another century. Until then, the cubs are living happily with Mom and adapting to the hustle and bustle of zoo life. They have a great destiny ahead of them, but their main job at the moment is being adorable.