Ever wondered?

September 12th, 2017 by Anna

You might have a few questions running through the back of your mind after watching this video of Jamie and Burrito playing:

Well we’ve got answers!

Question 1:
What’s the story with the big pink bottoms?
Answer: Female chimpanzees have large pink swellings (called “sexual swellings”) on their rear ends. These swellings vary in size both between individuals, and also in the same individual over the course of the menstrual cycle. They advertise a female’s fertility by letting a male know when the probability of conception is at its peak. In this video, Jamie’s bottom is not very swollen, and therefore she is not at peak fertility.

Question 2:
Why are Burrito’s testicles so large?
A: Since chimpanzees are not a monogamous species, and a female chimp may have multiple mating partners in a relatively short window of time, male chimpanzees engage in what is known as “sperm competition” – a male who can produce a large number of viable sperm has a better chance of producing offspring. Large testicles are useful for accommodating these large quantities of sperm. Additionally, Burrito has a chronic heart condition that can lead to swelling in the scrotum.

Question 3:
Do the chimpanzees ever mate with each other?
A: No. Many chimpanzees who grow up in impoverished, unnatural situations (like research labs) often develop abnormally and don’t exhibit typical social and sexual behavior. It’s also possible that the Cle Elum Seven chimpanzees consider themselves a family after living together as a group for so long, and therefore don’t view each other as viable mating partners. As an added precaution, Burrito has had a vasectomy.

8 Responses to “Ever wondered?”

  1. tobin says:

    I am concerned to learn of Burrito’s heart condition. May I ask what it is, and how it is treated?

  2. Kathleen says:

    I found your answer to Question #2 interesting. Are Burrito’s testicles actually larger than an average chimpanzee in the wild? Are his testicles actually larger simply because of his heart condition?

    And Question #4 : Is this a standard game these two clowns are playing? A pushy version of Follow The Leader! I could hear Burrito (I think it was Burrito) laughing all the way around, silly boy. Totally cracked me up!

    • Anna says:

      1.) Burrito’s testicles will sometimes swell (take on fluids) due to his heart condition. They don’t look particularly swollen in this video though.
      2.) Lots of people enjoy that game 🙂

  3. Nancy Poe says:

    Is there a social significance to the chimps throwing “excrement” at each other?

    • Anna says:

      Hi Nancy,

      Generally Jamie (our feces thrower) only targets humans. Feces is a powerful tool for her to get what she wants from those she cannot directly get to (we never go into an enclosure with the chimps). She is very smart and has learned how much humans dislike getting poop on them, so she knows she can manipulate our behavior with the mere threat of something being tossed our way.

      We have seen Negra throw things at Burrito as a way of trying to get him to calm down and stay away from her, but generally the chimps can make physical contact with each other so that usually eliminates the need to throw things.

  4. CeeCee says:

    Wow …How lucky for you Humans!