One hyena's spit is another man's treasure

We’ve talked about a lot of projects on this blog, but somehow I’ve failed to mention my favorite: saliva collection. It’s hard to believe anyone would get excited about hyena spit, I know, but bear with me. You’ll understand.

The process starts out here, with a tub of vegetable fat, some rope pieces, and an episode of my current favorite TV show playing in the background.

The ropes get a knot tied in one end, then they’re slathered with a thin layer of Kimbo. The final product ends up like this:

Next, the ropes are slotted into a hollow stick, with a bolt over the knot to keep the rope in place. Now we’re ready to go fishing for cubs.

 Whenever we’re at a den, we put the saliva sticks out the windows and brace ourselves for the best game of tug-o’-war ever. The Kimbo entices cubs to chew on the rope, drooling all over it in the process. Saliva carries a lot of hormones, so our goal is to collect samples from cubs before and after they do an exciting behavior, like play or an aggression. The ‘before’ sample gives us a baseline, while the ‘after’ sample lets us see how the cub’s hormones have changed in response to that behavior.

Mandrake demonstrating proper chewing technique

The actual saliva collection can be as tricky as it is fun. Cubs can start out enthusiastic, but lose interest and wander off to chew something more exciting (like the tires) before we’ve gotten enough of their saliva. We also have to ensure only one cub ever touches the stick so we know there is no cross-contamination of hormones. That can be quite difficult when there are 12 rambunctious cubs at a den, all anxious for a nibble of some of that tasty Kimbo. Keeping two hands on the stick at all times is also very important – those tiny hyenas can tug!

Yours truly about to do battle with Butcher - one of our most notorious chewers. Infamous for the dual sins of trying to yank the stick out of your hand, and attempt to saw the rope clean off the stick. Those meat-slicing teeth can do a number on rope!

Once we have a slimy, spit-soaked rope at the end of our stick, we’re ready for the next step. The rope is removed from the stick and put into one of these special tubes.

When centrifuged, the tubes allow saliva to be pulled out of the rope down into the lower section of the tube, while the rope stays in the top. Then we can throw away the rope and transfer the saliva to a cryotube to be frozen, awaiting transportation back to the US.

If you’d told me a year ago that tug-o’-war with a passel of hyena cubs would be part of my daily routine, I would have laughed in your face. But now I can’t imagine my life without it!