We’ve never given much thought to how sloths give birth, but like the rest of the Internet, we watched this recent video of a sloth mother high up in a canopy popping out a baby that falls, hangs precariously by its umbilical cord for a few seconds before being deftly scooped up by its mom, with our hearts in our mouths.
As birthing videos go, this was pretty wild.
Sloths spend the majority of their lives in trees, only visiting the ground to poop (around once a week) and perhaps find a new tree, both of which leave them vulnerable. Instead, they’ve learned to juggle everything high up in the canopy, from sleeping and eating to mating and, yes, giving birth. However, it’s unclear if the anxiety-inducing behavior captured in this video is normal for sloths or this duo was just incredibly lucky.
The video, captured by tour guide Steven Vela near Arenal Volcano National Park in Costa Rica, shows a three-toed sloth give birth to its young – fun fact, sloths are one of the few animals whose young we don’t have a name for – while hanging from a branch. The baby immediately falls, dangling from its umbilical cord until the momma sloth grabs it, hugging it to her body, and begins licking it clean, looking mightily unperturbed by the drama.
“That was something amazing,” Vela told National Geographic. “I think I will die and I will never see something like that [again].”
This is probably true, as witnessing sloths give birth is incredibly rare. Even Vela himself had no idea the sloth was in the late stages of labor when he pulled the tour vehicle over after spotting it.
Sloths in general are secretive and slow to the point of sedentary, so studying them in the wild is hard. The rare occasions when sloths have been observed giving birth show that they try and place their hands under where the baby will emerge, and that young that have slipped and hung on by the umbilical cord have simply been picked up by the mothers. However, there haven't been enough observations to know if their umbilical cords have adapted to be super strong for this unusual birthing method or these births witnessed just happened to go this way.
"It’s not known whether the behavior of the baby hanging by its umbilical cord is typical of a sloth birth, as very little data on this currently exists – but it does seem unusual," George Sunter, team leader of small mammals and two-toed sloth keeper at ZSL London Zoo, told IFLScience. "What we’ve witnessed here at London Zoo is that babies are born ready to go and can cling onto their mum from the minute they are born."
“The length of the umbilical cord is also not known to provide any particular benefit during birth, or so far as is evidenced in the literature," Sunter added. "It looks like this fall might have been accidental, but from our experience, the young are pulled out by mum who places the young on her stomach. The female then sits in a cradle position, ready to help the young find its footing before cleaning the young off and consuming the placenta later.”
The Zoo only has two-toed sloths, but Sunter told us observing births in captivity is also incredibly rare, having only witnessed one in over a decade working with the species.
"Births have been observed in the wild before but rarely filmed," Sunter said. "Sloths are hard to locate in their rainforest habitat, due to their cryptic and slow-moving behavior. Having such unique species like two-toed sloths in conservation breeding programmes in zoos, provides us a window of insight into rare behaviors like births – enabling us to collect essential data on sloth gestation, time of births and interbirth periods, helping us to understand more about this threatened group of animals."
So to capture it happening in the wild will be incredibly useful for conservationists. Whether this is a normal sloth birthing technique or not, it only seems to be us having anxiety over it. The sloths, like everything, seem to take it in their stride.