Tetrapod Zoology

I really like sloths, but one of their recently discovered habits might make me like them a little bit less…

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As recently reported by Eckhard Heymann and colleagues, Linnaeus’s two-toed sloths Choloepus didactylus at the Estación Biológica Quebrada Blanco in north-eastern Peru have developed the delightful habit of climbing into an outdoor latrine building, seeking out the latrine contents AND EATING THEM (Heymann et al. 2010).

The behaviour was first reported in November 2001 when a sloth was discovered hanging from the wooden bars within the latrine. “It was scooping with one hand from the semi-liquid manure composed of faeces, urine and toilet paper and then eating from the hand” (Heymann et al. 2010, p. 1 of preprint). This wasn’t a one-off. More than 25 additional reports of sloths visiting and feeding in the latrine were made, and in fact the behaviour only stopped in 2007 when wire mesh was erected around the building. Good photos were taken, and two are reproduced here. The photo below shows a mother and baby emerging from the latrine [from Heymann et al. (2010); photos by M. Stojan-Dolar].

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Why would a sloth want to climb into a latrine and eat human, errr, waste material? Heymann et al. (2010) make a few suggestions. Were the sloths interested in the faeces for nutritional reasons? Were they drinking the urine because they required the salt? Or were they interested in the insect larvae that were present? We don’t know: at the moment the reason for this behaviour is totally enigmatic. Indeed it’s possible that this behaviour will turn out to be widespread. After all, sloths live close to people in many places. Heymann et al. (2010) further speculate that sloths could act as vectors of human diseases and parasites as a result of these latrine visits.

Depending on your perspective, sloths might just have become even more interesting than they already are…. or, they might have become a lot less cute, and a lot more disgusting. Having thought about it, I’m actually not that bothered, and I still think sloths are neat and fascinating. But I think I might avoid touching them, cuddling them, or sniffing them from now on.

Thanks (again) to Glyn Young for the heads-up Back to gekkotans next.

For previous Tet Zoo stuff on sloths see…

And for other xenarthrans see…

Five things you didn’t know about armadillos
What was that skull? (on glyptodonts)
I, Priodontes, the tatuasu
The anteater that wasn’t

Refs – -

Heymann, E. W., Flores Amasifuén, C., Shahuano Tello, N., Tirado Herrera, E. T. & Stojan-Dolar, M. 2010. Disgusting appetite: Two-toed sloths feeding in human latrines. Mammalian Biology doi:10.1016/j.mambio.2010.03.003

Comments

#1 Kirsi
April 26, 2010

Interesting 0_0 Was there any mention of infections in the skin or eyes of the sloths caught red handed? Probably would’ve been hard to spot GI-infections…
#2 James Davis
April 26, 2010

3 words:

bad breakfast reading

—

That said, this is a pretty interesting topic and I’d love to know more.
#3 Chad
April 26, 2010

Perhaps I should have waited a little later in the day to read this.
#4 Luna_the_cat
April 26, 2010

Uh.

Interesting, but…
yuck. Really, just Eeewwwwwwww.
#5 Robert McAfee
April 26, 2010

While a tad gross, this does add to our very sparse knowledge of the diet in Choloepus. Also seems to match the general assessment that two-toed sloths will eat pretty much anything. Looking forward to adding this tidbit to my latest papers!
#6 Erin
April 26, 2010

GROSS. Why was this the first thing I clicked on on Monday morning?!
#7 Kevin Schreck
April 26, 2010

Nature never ceases to surprise me. In a way, I’m glad that sloths aren’t as cuddly as so many make them out to be. It’s like when bonobos were discovered eating vertebrate meat: it broke another naive stereotype we had about animals, and showed a fascinating (though maybe a bit disarming) method of survival.
#8 holytape
April 26, 2010

Great, now I’ll have to learn the word for an irrational fear of finding a two-toed sloth in the latrine when you really really have to use the latrine.

Noah and dinosaurs.
#9 seabold
April 26, 2010

I remember having to use the “out house” in the country when I was younger and the big fear back then was spiders, snakes or a skunk. I thinking opening the door and seeing THAT coming up through it might scar a child for life.
#10 Robert
April 26, 2010

I know it’s not scientific or objective, but…

What dirty buggers!
#11 Zach Miller
April 26, 2010

That’s…horrifying.

Completely unrelated question: Aside from also being sloths, how do extinct ground sloths relate to modern sloths? That is, did ground sloths come out of the trees, or did tree sloths get up off the ground? Do modern sloths have a good fossil record? Is one group ancestral to the other in some way? Did ground sloths ALSO frequent ancient man’s prehistoric latrines?
#12 Olga
April 26, 2010

How on earth could this be beneficial to them in any way?!?! Even if they are getting salt from the urine, or insects, the sheer amount of bad shit in there (excuse the pun) must far exceed whatever use they get out of it.

Well, I suppose in a little while we will see if this behavior gets ‘selected out’ or not
#13 Jelle Zijlstra
April 26, 2010

Zach: The two living sloth genera (Choloepus and Bradypus) have no fossil record, but there are tons of fossils of other sloths, which are probably all dubbed “ground sloths”. However, many of the smaller ones, like those in the Caribbean, probably did climb trees. I would guess that terrestriality is most likely primitive within Folivora.
#14 george.w
April 26, 2010

A friend of mine in high school once found a dead horse. As he approached it, a possum crawled out of the decaying cadaver and slowly made its way off. That was the grossest story I ever heard, until now.
#15 AmoebaMike
April 26, 2010

I never thought sloths were particularly fascinating. They are kind of cool looking, but aren’t most mammals? Anyway… this is really disturbing. I don’t know the sloth’s typical habitat and can only hope that it’s not near where I go camping.

I can’t imagine this is a good thing for them. I’d love to know if they have immunity to the bulk of what’s found living in these pits.
#16 jck
April 26, 2010

Sloth in pic 1 appears to have a shit-eating grin.
#17 DD
April 26, 2010

Perhaps unlikely, but maybe the habit of hanging from something (the seat) causes a powerful feeding reaction. Sea otters only eat while backfloating, they avoid eating while in a vertebrate-normal upright posture, even tasty food.

Do folivorous sloths have diminished taste buds or olfaction? Folivorous-herbivorous Gorillas eat their own feces, maybe post-intestinal microbiotic processed organics emit a scent paralleling the scent of cheese to people, an aquired aroma. After all, consumption of decomposed milk wouldn’t be expected for a descendant of supposed frugivores.
#18 Sebastian Marquez
April 26, 2010

I’m enjoying the responses along the line of “bad breakfast reading”. I’ll bet I’m one of the many that make Tet Zoo the first stop of the day when checking the web.

Fascinating and disgusting.
#19 Sebastian Marquez
April 26, 2010

Zach: I think number 10 in Darren’s “10 things you didn’t know about Sloths” post answers some of those questions.
#20 Jerzy
April 26, 2010

Remembers me of a story that giant pitcher plants in Borneo evolved as a perfect latrine for tree shrews…
#21 Anthony Docimo
April 26, 2010

reading this, my first thought was “wait, don’t sloths *bury* their dung?”
#22 razib
April 26, 2010

dude. dude.
#23 Albertonykus
April 26, 2010

Somehow, I did not find this too gross. That’s one more interesting thing about sloths!
#24 Nathan Myers
April 26, 2010

I guess this means I like three-toed sloths better than two-toed sloths.
#25 deang
April 26, 2010

I know sloths are eaten by Harpy Eagles and other predators, but could this habit make them repulsive to some carnivores, either because of the smell and taste it gives their flesh or because of diseases carried?
#26 doug l
April 26, 2010

When it comes to human waste, dogs do this as well…and so do pigs.
#27 Squïrrel
April 26, 2010

Very interesting post.

Nothing wrong with eating faeces. I have a shortened colon and so don’t extract all of the nutriment from food on its first passage. For the second passage, I enjoy spreading it on toast with a lot of butter.

Oh, wait. That’s Vegemite.
#28 Adam F
April 27, 2010

This is perhaps the only time in my life I’ve felt glad that ground sloths are extinct. Imagine seeing one of those rise up out of your outhouse. Without modern glyptodonts, I assume they would look for food wherever they could find it.
#29 Hai~Ren
April 27, 2010

Maybe that’s why Sid was always hanging around Manny in Ice Age.
#30 djlactin
April 27, 2010

@ 26 and way OT:
Here in Korea one culinary specialty (which I will not try) is “ddong-duedji” (lit. shit-pig): pork from pigs that have been fed only human feces for their entire “lives”. (one way of recycling efficiently i guess…)
#31 kris
April 27, 2010

I’m thinking along the same lines as DD: maybe they are after some microorganisms?
#32 AD
April 27, 2010

Sloths otherwise eat nothing but leaves…maybe they needed some nitrogen/protein from carnivore dung? Perhaps Megatherium really did swoop down on sabertooth kills!

(A phylogenetic argument for needing extra protein might be that other xenarthrans all eat much higher protein foods, perhaps the ancestral state for xenarthra, and sloths aren’t as good at pure herbivory as say ungulates?)
#33 Valagos
April 27, 2010

That second picture, isn’t that a three toed sloth? Are both types of sloths guilty of this odd behavior? Always knew Xenarthrans were a fascinating and mysterious bunch, but this “peculiar” incident opens up a whole new chapter of questions about them. Does anyone know if any similar behaviors have been recorded elsewhere outside Peru? I live in a country were sloths are common, but I never heard of anything like this. On the other hand, sloths are suspiciously absent from the local wildlife menu. Perhaps the native cultures just knew better…
#34 Darby
April 27, 2010

An awful lot of mammalian feces consists of bacteria (usually at least 25%), as well as lost lining cells and some non-reclaimed breakdown products such as those that produce the characteristic color, so there would be nutrition available. If there wasn’t, we’d be up to our butts in unrecycled wastes.

And if the sloths aren’t at all compatible with the active little buggers they’re ingesting, disease wouldn’t be an issue.

Still weird, though.
#35 Practically Uninformed
April 27, 2010

First off, I’m surprised that the sloths not only eat fecal matter, but figured out that it collects in a latrine. Was there any information about whether this latrine was a simple open-air seat, or a Port-o-Potty design? If it’s the second one, that’d be unusually clever for a sloth.

Second, I’d forsee the sloths having more problems with the toilet paper than the waste material itself. Who knows what effects that soothing aloe could have on a sloth’s digestive tract…
#36 Darby
April 27, 2010

You’ve been linked to -

http://blogs.herald.com/dave_barrys_blog/2010/04/nature.html

Dave Barry is an American humorist – he used to have a regular column, and he’s published several books. Now, so far as I can tell, he has a blog and tours in a purposely bad band.
#37 Zach Miller
April 27, 2010

I used to read Dave when he had a column in the papers. I’m surprised he’s still writing.
#38 KW
April 27, 2010

I’m going to have to agree with the second post, I had happily already finished eating upon reading this.

Odd, makes me glad I’m not a sloth. Not too many mammals that I know of that go for omnivore/carnivore poop.
#39 Robert Kolk
April 27, 2010

Here’s slothie!

One more thing we didn’t know about sloths.
#40 David Marjanović
April 28, 2010

some non-reclaimed breakdown products such as those that produce the characteristic color

Bilirubin and biliverdin aren’t good for anything much. What else is there?
#41 Raymond Ho
April 28, 2010

Silly sloth, too lazy to even chew its own food!
#42 bio
April 28, 2010

Excerpts from the diary of Martin, the sloth:

March 17, 2008:
Derek came up with a great idea. There are these two-leg walking devils, and especially those of them who cannot stop watching us every minute of our lives – let’s just drive them crazy! We’ll think of something to do, something completely unreasonable and stupid, out-of-the ordinary that leave them toitally at loss for the rest of their whole miserabée lives… So, let’s rev up these grey cells…

Feb 12, 2010:
Jarvis – what a uick thinker that guy is!!! – has THE idea!

bio
#43 John Conway
April 28, 2010

That first photo has internet meme written all over it: “I’m in ur shitbox, eatin’ ur pooz!”, “hai gaiz”, “can i haz feeseez”, “I brought you a log, but I ated it” etc.
#44 Lso
April 28, 2010

This may get flagged as grusomely inapropriate but …. Two sloths one stall??
#45 Dartian
April 29, 2010

DD:

Do folivorous sloths have diminished taste buds

No, or at least not relative to other xenarthrans (Sonntag, 1923).

or olfaction?

One study (Pirlot, 1980) suggests that the three-toed sloth Bradypus has relatively smaller olfactory bulbs than an armadillo. On the other hand, the hero of Darren’s post, the two-toed sloth Choloepus, has an olfactory organ that is fairly large – or at least not obviously smaller – than in other similarly-sized mammals (Adam, 1999; Yours truly, personal observation). I’d wager that by mammalian standards, the (two-toed) sloths’ sense of smell is neither particularly keen nor particularly poor. But we need more quantitative data to settle that question.

References:

Adam, P.J. 1999. Choloepus didactylus. Mammalian Species 621, 1-8.

Pirlot, P. 1980. Quantitative composition and histological features of the brain in two South American edentates. Journal für Hirnforschung 21, 1-9.

Sonntag, C.F. 1923. The comparative anatomy of the tongues of the Mammalia. IX. Edentata, Dermoptera, and Insectivora. Proceedings of the Zoological Society of London (34), 515-529.
#46 Ogre Magi
April 29, 2010

Where can we see the rest of the sloth latrine pics?
#47 Nathan Myers
April 29, 2010

Valagos #33: My preference for three-toed sloths didn’t last long.
#48 Hai~Ren
April 30, 2010

Valagos: I don’t know sloths that well (haven’t seen one personally yet), but two-toed sloths have three digits on their hind feet. Is the second picture a view of the sloth’s back?
#49 DD
April 30, 2010

Dartian, thanks, interesting. I was thinking, that since folivorous proboscis monkeys can eat leaves and ‘green’ fruits but never ripe fruits (which produce bloating), that perhaps a sloth could be somehow attracted to and be unaffected by pre-processed ripe fruits in feces (assuming that humans (and monkeys?) in tropical rainforests consume much fruit). Also there might be a parallel in armadillos having insensitivity/immunity to formic acid of fire ants, and sloths having insensitivity/immunity to plant leaf alkaloids. Armadillos are attracted to corpses, to get at the decomposer larval insects, but I don’t think sloth toilet-feasting is related to any attracted insects. A tangent: sloths and sea cows are unique in having abnormal vertebral counts, could algae-coated tree sloths (which are good swimmers) have derived from a miocene equatorial flood-forest variant of the “marine” sloth of Peruvian desert shores? I think the marine sloth evolved dense armadillo-like skin (manatees & alligators have very dense skin) and sunbathed on desert beaches between feedings on seagrass (like marine iguanas), using its claws both for burrows and clutching/raking seagrass. See: http://catalogue-of-organisms.blogspot.com/2008/04/swimming-sloth.html
#50 David Marjanović
April 30, 2010

could algae-coated tree sloths (which are good swimmers) have derived from a miocene equatorial flood-forest variant of the “marine” sloth of Peruvian desert shores?

Highly unlikely, because the marine sloths were a sideline, and because the tree sloths aren’t each other’s closest relatives: one of them is the sister-group to all other known sloths or something, the other is a megalonychid.
#51 ambulocetacean
May 1, 2010

Hee hee. Poop sloths! From now on whenever anyone is being lazy and disgusting I’m gonna call them a poop sloth. And direct them to this page.
#52 Dino
May 1, 2010

So they don’t like their own feces but they enjoy eating what others leave behind?
Hummmm …. I think even dogs do that.
#53 ambulocetacean
May 2, 2010

John Conway #43. I thoroughly agree that poop sloths are the new LOLcats. You can see some proto-memery here.
#54 Dartian
May 4, 2010

DD:

A tangent: sloths and sea cows are unique in having abnormal vertebral counts, could algae-coated tree sloths (which are good swimmers) have derived from a miocene equatorial flood-forest variant of the “marine” sloth of Peruvian desert shores?

By ‘abnormal vertebral counts’ I presume you mean their number of neck vertebrae? The basic – and, I suspect, insurmountable – problem with postulating similar ecological selection pressure (i.e., aquatic living, if I understood correctly what you were getting at) as the explanation for sloth and sirenian cervical vertebrae count is that their respective neck vertebrae numbers are unusual in different ways:

-Strictly speaking, ‘sea cows’, i.e., dugongs Dugong dugon, are not unusual regarding their neck vertebrae counts; dugongs have the standard mammalian seven. Manatees Trichechus, on the other hand, have a reduced number of cervical vertebrae: they have only six (Buchholtz et al., 2007).

-Among extant sloths, three-toed sloths Bradypus have a greater number of cervical vertebrae than usual for mammals: they have eight to ten, with nine being the typical number. Two-toed sloths, on the other hand, have fewer cervical vertebrae than usual for mammals, but there is variation even among Choloepus species in this regard. The common two-toed sloth C. didactylus usually has seven neck vertebrae, like most mammals, but in Hoffmann’s two-toed sloth C. hoffmanni neck vertebrae count varies from five to seven, with six being the typical number (Buchholtz & Stepien, 2009).

In short, there is no discernible pattern, or at least no ecologically correlated pattern, in the variation in neck vertebrae count in these mammalian taxa: the aquatic manatees and the arboreal Hoffmann’s sloth have fewer cervical vertebrae than mammals typically; the aquatic dugong and the arboreal common two-toed sloth have the typical mammalian cervical vertebrae count; and the arboreal three-toed sloths have more cervical vertebrae than mammals typically.

References:

Buchholtz, E.A., Booth, A.C. & Webbink, K.E. 2007. Vertebral anatomy in the Florida manatee, Trichechus manatus latirostris: a developmental and evolutionary analysis. The Anatomical Record 290, 624-637.

Buchholtz, E.A. & Stepien, C.C. 2009. Anatomical transformation in mammals: developmental origin of aberrant cervical anatomy in tree sloths. Evolution & Development 11, 69-79.
#55 C. Corax
May 4, 2010

Hey, how many of you have dogs that eat faeces? Yup, I thought so.

Just think of this as the first step in the domestication of sloths!
#56 kittenz
May 4, 2010

I envision various Giant Sloths, following herds of proboscideans, using those long arms and big claws to pulverize pachyderm patties.
#57 Ellen
May 7, 2010

Wow, that’s disgusting. I hope that’s a natural behavior that won’t kill them, instead of a pathological behavior caused by human disturbance.

And I want to see the internet meme from this.

[quote]“Great, now I’ll have to learn the word for an irrational fear of finding a two-toed sloth in the latrine when you really really have to use the latrine.”[/quote]

Does phyllophagapochoreteriophobia work?