The lesser capybara (Hydrochoerus isthmius) is a large semiaquatic rodent of the family Caviidae found in eastern Panama, northwestern Colombia and western Venezuela. It was recognized as a distinct subspecies of capybara in 1912, and was elevated to species status in 1991. It breeds year-round, with an average litter size of 3.5. Individuals may be diurnal or nocturnal and solitary or social depending on season, habitat and hunting pressure. The species is reported to be common in Panama but rare in Venezuela. It is threatened by subsistence hunting, the destruction of gallery forests and swamp drainage, specifically the swamp drainage of the Magdalena River. Its karyotype has 2n = 64 and FN = 104.