Prospective comparative studies of wild and captive sloths in Costa Rica


Bradypus variegatus (Xenarthra, Bradypodidae) and Choloepus hoffmanni (Xenarthra, Megalonychidae) are species from the tropical rain forest of the Caribbean and Pacific regions of Costa Rica. Both species are considered in serious threat of extinction.

Deforestation, agricultural activity, and an increase in human settlements are among the main factors driving sloth populations to extinction. Due to this new proximity to humans, sloths are also becoming a popular “pet” for the local people. Costa Rica maintains numerous captive sloths in zoos and rescue centers, primarily for educational purposes.

Sloths have intrigued scientists because of their unique physiology and behavior. As a result, sloths are extensively studied, both in their free-ranging environment and in laboratories.

sloths2However, unlike anteaters or armadillos, for which the medical literature is provided, few veterinary publications exist on the sloths. To date, for instance, in PubMed (reference site of scientific peer reviewed publications), there is no publication on cardiology or abdominal ultrasound parameters in sloths.

The aims of this project, in collaboration with the Veterinary University of San Jose, is to conduct several pilot studies on wild and captive sloths.

All the proposed studies will be of great help for the sloths in zoos and rescue centers of Costa Rica in particular and for the scientific community in general.

Cardiology of wild and captive sloths

The aim of the study is to characterize and report echocardiographic findings in wild and captive sloths. With the intent to provide :

–  A comparative evaluation of transthoracic echocardiograms from clinically healthy wild and captive animals

– Reference values for use in cardiologic evaluations when a heart disease is suspected.

– Comparative prevalence of valvular regurgitations in wild and captive sloths.

To our knowledge, such prospective cardiologic study of wild and captive apparently healthy sloths has never been done.

Kidney ultrasound evaluation

Reported renal diseases of sloths include chronic renal failure, cystitis, and urolithiasis. It appears to be a fairly common problem in aged sloths, sloths3with reported mortality rates as high as 50% in populations of 10–15 yr old Choloepus hoffmanni and C. didactylus sloths. A commonly believed contributing cause of renal disease in this species is feeding diets high in protein and mineral levels.

Attempts to establish normal urinary values or find techniques to adequately capture urine would greatly benefit early identification of insufficiency and allow early treatment.

Moreover, there is currently no description of the normal renal ultrasonography in sloths.

Parasitology research

Sloths are hosts to a variety of gastrointestinal parasites, which are frequently associated with diarrhea.

Ectoparasites, such as ticks and mites, are generally considered to be nonpathogenic to sloths under natural conditions.

Sloths  also harbor a varied number of spe-cialized commensal arthropods such as moths, mites, and coprophagic beetles, in association with their feces.

Accurate identification of sloth parasites can help zoos and other institutions assess the risk associated with severe parasitism in their captive populations. Identification of these parasites will also lead to the establishment of effective prevention and control measures.