A while back I put up a post and a video showing the bizarre behavior of sloths when they have to defecate: once a week they make the long, slow climb down to the base of their tree, dump their load, and then retrace their steps up. I suggested four hypotheses for this behavior, and decided that the most likely one was to identify their location to potential mates. There were lots of comments, and most people disagreed with the “mating” idea because, after all, how would one sloth ever find another if they had to climb down a tree and sniff around other trees? It seemed inefficient. Now, Becky Cliffe from the University of Manchester claims she has some support for the mating hypothesis (I am putting below a comment she just added to the earlier post):
I am doing the study and I can shed some light on this matter! To cut a long project short, I have been monitoring sloth behaviour, reproductive activity, thermoregulation and metabolic activity for the last 12 months and can tell you that the defecating at the base of the tree is almost certainly linked to finding a mate.
You won’t find any literature on this at the moment but I can tell you female sloths have a very regular 28 day reproductive cycle, during which, they are in heat for 10 days. During these 10 days,they actually let out regular high pitched screams that attract males from up to 700m away, and they descend to the same spot at the base of the same tree daily to go poo/pee (even if it is just the tiniest amount!)
It also takes them an average of 31 days for food to pass from ingestion to excretion … amazing! And yes, their body temperature CAN fluctuate up 8 degrees over the course of a day. And the respiratory rate can range between 6 breaths per min to 120 !
Oh and the stuff about them being half deaf and half blind… completely false and I have no idea who spouted that one originally!! Very interesting animals 🙂
Just to show this is legit, here’s a YouTube video of Becky with baby sloths: