Friday Weird Science: Back off, Bro, that's MY teat!

Jan 27 2012 Published by under Friday Weird Science

One of the best things about being a science blogger is that every day, it seems, I learn something new. I mean, I learned something new most days before I was a blogger, but now, NOW I trawl the internet looking for the things that make you go OMG. And today, I found something that is wild and weird on two different levels.

This, you guys, is the binturong.

Awwwww.


(Source)

The binturong has a couple of cool and odd things about it. The first is that it apparently smells like buttered popcorn. Something to do with their scent glands. I hear that Laelaps is all set to ferret the secret of that out, so I'm focusing on something else odd, but which is actually common to several groups of mammals: teat ownership.

Schoknect, P. "Growth and teat ownership in a litter of binturongs" Zoo Biology, 1984.

Binturongs, aka Bearcats, are closely related to civets (the ones that poop out the uber-expensive coffee), and are native to southeast Asia. They live in trees, can make cute chuckling noises when pleased, and are generally adorable. And...the babies have teat ownership.

What is teat ownership? Exactly what it sounds like. It's when you have a litter of babies, one takes top left nipple, another takes bottom right, and ne'er shall they switch. Sometimes, in an effort to switch, the babies will actually fight a little to defend their teat. Teat ownership is a behavior that is common to cats, pigs, sheep, leopards...and biturongs.

What is the point of teat sharing? The hypothesis is that teat ownership reduces fighting among littermates for the good teats (yes, there are better teats), and ensures that most teats will remain pretty equally used. But does it really reduce fighting? Other studies have shown that there are still fights among cats, pigs, etc. So what about biturongs?

So this author wired up an attractive looking nestbox with a closed circuit camera (though how much would everyone love to see baby binturongs on the internet?!?!), and got a litter of binturongs. The author observed the cubs as they grew up, and looked at who suckled where, and whether they fought about it.

Binturongs have three pairs of teats, running on either side of the chest, traditional mammal-style, but only the top two pairs were active in this case. The top are the pectoral, and the bottom are inguinal. It turned out that the cubs picked their teat, and generally stuck to it, but when given the opportunity, they would pull shenanigans or fight to get to the left rear teat. It's where all the cool baby binturongs want to be. And boy did they fight for it! Giving each other cuts and resulting in little bald patches around their baby binturong eyes. Not to mention leaving some marks on the author, who noted that after the first weighing episode, she trimmed their nails so she didn't get scratched up getting between a baby binturong and his chosen nipple.

But it turned out they were fighting over that front left for a reason.

This is a graph showing the weight of the baby binturongs. You can see that two of them really outweighed the others. Those are the cubs that got the left rear and the right rear, with the left rear as the teat of choice. And it's obvious why. The left rear and right rear cubs got substantially bigger than the others, which the author suggests means they may give better milk (higher in fat) than the other teats. And a higher fat milk supply means a bigger baby, and a healthier one. That's a nipple worth fighting over.

Schoknecht, P. (1984). Growth and teat ownership in a litter of binturongs Zoo Biology, 3 (3), 273-277 DOI: 10.1002/zoo.1430030310

15 responses so far

  • Jenny Morber says:

    Wow. I had no idea that there was such a thing as teat ownership, and even more amazing that some teats give better milk. So cool.

  • DJMH says:

    What's the speculation on why the milk quality or quantity would be so unequal? Is it an offshoot of a biological oddity? Is it somehow better to produce a litter with some large and some small offspring, rather than a litter of all-medium-sized offspring? (assuming that the milk is a zero-sum game....)

    • scicurious says:

      You know I have NO idea. The discussion of the paper mentioned maybe the biturong lay more on one side than the other, changing accessibility, maybe there was higher volume of milk, but there's also been shown to be better QUALITY, which makes you wonder. I'll ask around on teh Twitterz.

  • Lori says:

    Don't ask a biologist - ask a veterinarian ;). If they are anything like cows, there are numerous reasons (infection, inflammation, fibrosis, etc.) that can cause milk to be different from teat to teat.

    • scicurious says:

      Thanks! Very true. I wonder if there are always consistently better teats than others? If so, is this always infection? I guess you'd need a whole tribe of biturongs to figure this one out.

  • [...] what happens later, when the little baby binturongs come along, see today’s Friday Weird Science by Scicurious. When it comes to teat ownership, those bitty bearcats are [...]

  • szescstopni says:

    It seems that the critter you refer to is binturong (Arctictis binturong). Just fix the typos (15), please, and remove this comment

  • Did they actually test the milk from each teat? Maybe the two cubs that got the rear teats were stronger to begin with, leading to both 'winning' the good teats and gaining more weight. Could there be some other reason that they prefer rear teats, like it's warmer there?

  • [...] what happens later, when the little baby binturongs come along, see today’s Friday Weird Science by Scicurious. When it comes to teat ownership, those bitty bearcats are [...]

  • stripey_cat says:

    Could it be that the healthier cubs were stronger suckers, and thus giving different feedback to their mother? I think (I'm not a mother!) that human milk production is highly dependent on the infant suckling, both in quantity and quality.

  • [...] what happens later, when the little baby binturongs come along, see today’s Friday Weird Science by Scicurious. When it comes to teat ownership, those bitty bearcats are [...]

  • sheila says:

    I tandem-nursed my older two, and the oldest baby (they were separated by 18 months) firmly preferred a certain boob. This had more to do with the milk flow dynamics which were the result of the shape of the nipple (one was more inverted), than anything else, I suspect. The firstborn got both boobs because he was the only one at the time. I put the new baby, when she was born, on the one with better flow, and the firstborn was furious, would try to push his sister away from "his" favorite boob and glare resentfully at her while nursing from the unpreferred one. He would even push at her face if he thought I wasn't paying attention, which is kind of amusing, since it was my chest, so of course I was paying attention, even if I was reading a book or something at the time. He is 16 now, and I think he never forgave his sister for "taking his boob" - he is unreasonably competitive with her.

  • [...] John (a.k.a. dendroica): Friday Weird Science: Back off, Bro, that’s MY teat! | Neurotic Physi... (scientopia.org) [...]

  • Wow, what a nice article!
    Frankly speaking, I've never heard of the binturongs.
    To say nothing of the fact I've never seen any!
    That one on the picture looks so cute! Your article made me watch more about these animals.
    Thanks!

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