“There’s nothing like biting off more than you can chew, and then chewing anyway.” To say that I’ve been busy recently would be an understatement. After five and a half years of studying sloths, the more I learn – the more questions I have. I have been juggling a lot of new research with ongoing projects, and there are many more bubbling on the horizon. Here’s a little sneak peak into some of the work that has been keeping me so busy.
Sloth metabolism – how slow is slow?
Sloths are thought to have one of the lowest metabolic rates of any mammal – but exactly how slow is slow? In May I was joined at the sanctuary by Professor Rory Wilson and metabolic expert Dr Mike Scantlebury, and together we began an exhaustive study into the resting and field metabolic rates of both captive and wild two-fingered and three-fingered sloths. This ambitious and ongoing project has many different branches, but a good proportion of my time lately has been dedicated to running our metabolic chamber (yes, this is just as complicated as it sounds). Although I can’t go into too much detail at this stage, ‘running the chamber’ basically involves me and my research assistant (Sarah) being locked in a small white room, scribbling down oxygen and carbon dioxide values every two minutes – for up to 13 hours at time! Not exactly the jungle sloth tracking that I am used to. Despite the endless hours of data collection, this project is no doubt going to produce some incredible and exciting results that – knowing sloths – will probably surprise us all. I can’t wait to be able to share more with you on this front!
Sloth muscles – stronger than you think!
I was also joined in May by a team of biomechanics experts from Youngstown State University – including Dr Michael Butcher and his students. Very little has been documented on the anatomy and physiology of sloths, particularly the three-fingered Bradypus. Dr Butcher and his team specialize in muscle architecture properties of the forelimb – basically how the structure of the muscles are specialised for function. Sloths are known to have the lowest muscle mass relative to body size of any mammal (approximately 30% less than other mammals), yet they have incredible strength and power capabilities with a surprisingly high resistance to fatigue. Sloths can literally suspend themselves in the crucifix position without even trying. They could make even the best human gymnast look weak. With Dr. Butcher and his team, I spent 10 days carefully dissecting sloths that had previously died of natural causes at the sanctuary. The results were impressive to say the least! Our data is still being processed but we will share the paper here when we have it published.
The human problem – genetic deformities in sloths
At the beginning of this year I ran an Indiegogo campaign to fund our genetic research into sloth deformities – with amazing help from the public, we hit our target of $15000 and the project is well underway. I currently have hair samples from 80 three-fingered sloths and over 150 two-fingered sloths. I also have hair samples from the six deformed babies that have been rescued by the sanctuary over the past few years. All of these samples are going to be exported to Swansea University in September for genetic analysis and we hope that the results are going to shed some light on why so many baby sloths are being found with birth defects. It’s a mystery that we are going to get to the bottom of.
Getting personal – a study of sloth digestion
I have been conducting an ongoing investigation into the digestive rate of both two and three-fingered sloths for the past 12 months, and now we are finally nearing the end! I am hoping to look at how temperature affects the rate of food passage through the gut (which is by far the slowest of any mammal). To do this, we have been feeding the sloths a harmless digestive marker, and collecting the faeces for months afterwards. Recently, I have been faced with the delightful task of homogenizing the hundreds of frozen sloth poo samples that I have accumulated in the freezer – me and Sarah have spent 13 days doing this and have been through two blenders so far (yes, those are human food blenders bought especially for sloth poo – science in the ‘field’ usually involves making the most of what we can get our hands on)! But as I have learnt, that’s science!
The Backpack Project
Progress with the backpack project as been somewhat slower than usual – partly due to our other research projects demanding my time, and partly due to the continuous downpour that has been relentlessly soaking the Caribbean. We have had record breaking rainfall twice in the last two months, and this week an emergency red alert (the highest level) was issued for the Limón region due to the heavy rains and flooding. My usual jungle path has been completely submerged and crossing the river has become impossible. Thankfully, the water tends to recede just as quickly as it rises – but we really need the rain to stop!
I did manage to tag another wild two-fingered sloth last month with a tracking backpack. This big female (named Nutmeg) was rescued from the edge of a busy road and we decide to release her into the protected forest surrounding the sanctuary. We filmed her release with Jeff Corwin for his Ocean Mysteries series – working with Jeff and his crew was an absolute pleasure and Nutmeg played her part perfectly. She was released into a big almond tree on the edge of the forest (a favorite food of two fingered sloths) and there she remained for the next 8 days!
They say that nothing worth having comes easy – and I’m going to be carrying that thought with me for the next few months. We have more projects in the pipeline and I will be catching up with many of the wild sloths that currently have tracking backpacks. In addition to the research described here, I am starting to work with micro-temperature loggers and will be collaborating with some local botanists to begin identifying the species of trees favored by the wild sloths that I have been tracking. We have a lot of work to do, but I am excited about the future and the research that is developing. Watch this space for the results!