arousal Archives - Chimpanzee Sanctuary Northwest

This morning, I caught Missy in a rare moment of stillness.

But not for long. Suddenly, she stood up and began scratching vigorously with both hands.

Chimpanzees display self-scratching behavior when they are physiologically aroused. It’s thought that the scratching may be a response to sensations in the skin resulting from autonomic processes like piloerection (hair standing on end). In other words, something excites you, you involuntarily get goosebumps, and in turn you feel like scratching your skin. Often this occurs during times of stress, like when a subordinate male sits next to a dominant male. But sometimes the arousal is positive, like when Missy wants to play.

After scratching, Missy ran over to Foxie, took one of her trolls, and ran away across the shaky bridge.

Foxie doesn’t like to walk on anything that feels unstable, so the best she could do was to climb up to Missy’s level on the platform.

Missy wanted to keep the game going, so she ran back to Foxie and sat on the end of a beam.

And then, when Foxie wasn’t looking, she disappeared down the ladder.

Missy ran over to the tunnel, tempting Foxie come rescue her troll.

Foxie didn’t respond, so Missy climbed atop the grassy mound, teased Foxie one last time, then took off up the hill.

That did the trick.

Foxie used to get anxious when the other chimps took her trolls, but now she enjoys it. In fact, she doesn’t even try to get them back right away. Allowing her friends to hold onto her dolls while they play chase is Foxie’s way of keeping the play session going.

Missy took that as a cue to make the game even harder. She climbed back up where the troll would be tantalizingly out of Foxie’s reach.

Again, Foxie did her best to get close to Missy.

But after a while, she’d had enough, so she placed her one remaining troll on her back and headed back towards the greenhouse, perhaps hoping that Missy (and her troll) would come along too.