Koala Boys: Best Buds

The best friends share space during quarantine.

The best friends share space during quarantine. Thackory is on the lower branch.

Thackory and Milo are two juvenile male koalas who just recently returned from a loan*, graduated with flying colors from our quarantine area, and are settling into their bachelor digs in the San Diego Zoo’s awesome new Australian Outback. These kids have had a busy first 2½ years, and with all of the adventures they’ve experienced together, they have formed a strong and unique bond.

It all started the summer of 2011 when both koalas were born within weeks of each other here at the Zoo. Since they were males and so close in age, the decision was made to house them together as soon as they were out of the pouch and on their own to conserve space—we are a conservation organization, you know! Always being roommates seems to work well for these two, since most male koalas are typically not housed together. This was the start of a beautiful friendship.

At home in the grocery store!

Milo is at home in the grocery store!

Although Thackory and Milo have always lived together, during their first few days back in San Diego, they were housed next to each other in quarantine with no access between the rooms. This is the usual protocol for male koalas since they tend to be single, solitary, and territorial. But soon word spread that these boys were buddies, and the common door was opened. To be honest, they didn’t even notice! Giving each other a very subtle “Hey, what’s up?” look, they proceeded to chow down on the closest branch of tender eucalyptus.

As per protocol—there’s that word again—hospital keepers weighed our quarantined koalas every day during their first week here. This is a great way to monitor how the animals are reacting to their move. Typically, koalas start at a certain weight on Day 1 and then have a dip in weight the next few days, ending on a high note usually at or above their incoming weight on Day 7. Daily weights meant lifting each animal out of his tree, putting him on a scale, and then returning him to his room, consciously placing him on the same side and sometimes the same perch as his roommate, just to test the relationship to make sure it is still compatible. These laid-back boys always passed this test every time; since they’ve grown up together, they’ve always had to share. And as my kinder at home states, “sharing is caring.”

Travel, new surroundings, and different eucalyptus impact these sometimes-sensitive animals. Having eucalyptus as their only food source, keepers watch closely to make sure the koalas are eating an appropriate amount. Daily weights are a very helpful monitoring tool, but it can be difficult to monitor intake searching through a huge bundle of “euc” to see what’s been nibbled on, since some koalas choose to eat just the tips of certain species. That is when we look down. You can tell a lot about how much a koala is eating by the amount of poop it produces. Yes, there’s that fun topic again!

Thackory and Milo had an amazingly uneventful 30-day quarantine period, living together in the same space and sometimes on the same perch. Peering through the huge euc bundle, we’d see a two-headed-koala or notice five legs hanging out among the leaves. This unique and space-saving bachelor group is a testament to conservation!

We hope this nonchalant and compatible pair continues to share space; since koalas mature around the age of four, our fingers are crossed that their beautiful friendship will continue through their adult years. We wish these buddy bachelors all the best!

*A little side note about our Koala Loan Program: At this time, the San Diego Zoo houses 23 koalas, but technically, we have over 60 in our collection. How is that possible? There are currently 40 animals out on loan at other facilities around the world. Our Koala Loan Program serves as an amazing education and conservation tool. Partnerships and agreements are made between our facility and other accredited facilities to share our koalas for display and husbandry-training purposes, as well as breeding opportunities. This is a great way for people to learn about koalas, and the funding from these loans goes directly toward koala conservation!

Kirstin Clapham is a senior keeper at the San Diego Zoo. Read her previous post, Zoo Hospital: Leopard Youngsters.

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