Luna update: February 2022
2021, The year of Luna with Sol
We added Luna and Sol to the Urban Sloth Project in March 2021. Once Luna was fitted with a collar in March, we were able to track her and baby Sol every day. We estimated baby Sol to be around three or four months old at this time, but sloths are very difficult to age–we were unable to weigh Sol, which is usually the best way to guess a baby sloth’s age.
In August we began to see Sol becoming more curious about his surroundings; at first, it was only a limb or two reaching into the liana vines, but one day we came to track them, and we found him sitting next to Luna instead of on her belly!
He wasn’t quite ready to leave Luna entirely, and there was a lot of him going back and forth between his mama and the branches. We felt like proud parents watching little Sol gain his independence.
By October, we confirmed that baby Sol was all grown up! We had consistently seen him separate from his mother, until one day they were no longer sharing the same tree.
In most mammals, once the parents raise the young to independence, the young are expected to disperse and find their own territory. With sloths, once the baby is ready, the mother leaves them with a portion of her own territory and moves on herself.
We were able to witness this with Sol, to whom Luna left her very favorite tree, while she moved further south. Luna moved all the way to the other side of the lot they occupied, leaving the tree she raised her baby on to her grown-up boy. According to our calculations, Sol gained independence at 10 months old.
December: Sol is finally grown up
We still tracked Luna every day, but with no radio collar, it has been hard to find Sol! We have seen him around a few times in his little territory that borders his mother’s, but if he decided to make a big move we probably wouldn’t know about it. Luna has continued to thrive in the new, more southerly portion of her territory, which she shares with a number of other sloths.
One Saturday in mid-December, when the tracking team went out to find Luna, they instead found massive deforestation occurring, with chainsaws and bulldozers cutting down their trees. Happily, the community made a big protest about this, the tree felling was stopped, and has not resumed while the relevant authorities are looking into it.
A new year, a new baby!
We’ve been waiting for it ever since Sol moved on to find his own territory, and the day has finally arrived: Luna has a new baby! Baby Celeste was born in the last week of January (2022), and is sooo tiny!
Luna probably went into heat and conceived shortly after Sol started independently exploring in August. Although we are not precisely sure of the gestation period of three-fingered sloths, we estimate it is approximately six months. Researchers have not yet had the opportunity to observe a three-fingered sloth during the entirety of her pregnancy, so this gestation period is still being determined.
Luna’s territory is a good one for sloths
Or it would be if they’d stop cutting down the trees. Several three-fingered mothers are known to inhabit the area. Thus when Sarah stopped by Luna’s territory while covering a shift for Ames (who was quarantined with Covid) she did not immediately recognize the mama sloth with a days-old baby velcroed to her side as our lady Luna.
Since the area’s deforestation in December it’s not unusual to find crowds of tourists gathered around the lone guarumo trees, watching and snapping pictures of the half dozen three-fingered sloths that can be seen on any given day. When the crowds are looking up, we know everything is in order and the Sloth Star of the Day is high in the trees and safe. When the crowds are looking down at the ground, we know there is most likely a sloth trying to get somewhere, and it’s time to intervene. The intervention consists of politely explaining to people that the sloths are not here to meet them and asking the tourists to give them a little space so the sloths can get where they are going.
This is what was happening on a Friday when Sarah spotted a crowd and went to see whether the sloth needed an advocate or not. The sloth in question was crawling across an obstacle course of felled trees and organic debris, trying to get from one tree island to the next.
At first, Sarah was quite confident that no, this was not Luna–because look at that tiny baby!–but once she pulled out her own phone camera she was able to zoom in and see the antenna of Luna’s tracking collar. Our favorite mom was a mother all over again.
Sarah got some great footage to use as evidence that reforesting and bridge-building in this part of the maritime zone needs to be made a priority, because who can resist helping out baby sloths?
At least now we know why Luna disappeared on us for a few days; clearly, she just wanted some peace and quiet to deliver her new daughter, currently weighing in at around 300 g. That’s about 10 oz, or about two average-sized smartphones. (For the record, we don’t actually know that the baby is a girl. Right now we’re guessing, and we figured since we called her last baby a boy we needed to even up the gender ratio a bit.)
Though he won’t contribute much to raising little Celeste, we think we know who the father is, as there is only one mature male in Luna’s territory. We don’t have a name for him, but maybe his newest daughter will grow up to look like him!
The babies of Luna
The sex of the babies will remain a mystery for some time as all genitalia are hidden internally in three-fingered sloths. The best and least invasive way to determine male from female is to look out for the brightly colored speculum that develops on all male Bradypus sloths (with the exception of the maned sloths). Unfortunately, the speculum does not develop until sexual maturity (at approximately two years old) which means that it can be difficult to know the sex of sloths before this point.