Renal morphology of Bradypus torquatus

Abstract

Among the Xenarthras, sloths present a hydric ingestion restricted to water from leaves, fruits, and vegetables. As a first approach to verify whether these animals have some morphophysiological difference which could justify or compensate this low hydric ingestion, the renal anatomy of these animals was investigated, particularly that of maned sloth (Bradypus torquatus). Kidneys from these animals were macroscopically analyzed, through light microscopy and scanning electron microscopy. The Bradypus torquatus kidneys are bean-shaped paired organs, located dorso-cranially to the pelvic girdle, between the peritoneum and the posterior abdominal wall. The use of histological techniques allowed us to identify, in the cortical region, the renal corpuscles and tubules, and, in the medullary region, a significant amount of interstitial tissue with a collecting duct. The results of this study showed that, although Bradypus torquatus doesn’t drink water directly, its kidneys doesn’t differ from that of most mammals, presenting the same anatomical structure, suggesting that these animals fully reach their hydric needs, basically by consuming leaves, fruits, and sprouts. Nevertheless, in order to confirm this hypothesis, studies on the effectiveness of water reabsorption, such as the renin-angiotensin-aldosterone system, must be carried out.

Keywords

• Bradypus torquatus
• Maned sloth
• Renal morphology