Although the current population size of the pygmy sloth is unknown, it is believed that there are at least 79 at minimum living on their island, at the most there could be less than 500 however. This species however originates within the huge diversity of the Xenarthra group, containing armadillos and anteaters, at one time present in the Pleistocene period. Initially several giant sloths known as Ground Sloths, one of the first and largest sloths to stir, as well as other species were prominent in North America, with a large diversity within them until 10,000 years ago, when a large majority of mammals, including a large amount in the Xenarthra, were made extinct. Only 6 species of sloth are known to have survived, one of those being the pygmy sloth, which isolated itself from its brethren approximately 1000 years later, when they had settled on the island and the sea levels rose separating them from the mainland. The pygmy sloth has therefore undergone extremely rapid body size evolution following the isolation of its founder population in the early Holocene Epoch. Bradypus pygmaeus was first discovered very recently in 2001, when a steady number for the island was present, however this population began to take great notice of in 2006 when its habitat began to disappear, due to deforestation of locals and other travelers and so over the past 10 years their numbers began to decrease and are still decreasing today.
As shown by the data in the graph, the pygmy three toed sloth population is decreasing at an alarming rate, corresponding to the decrease in their habitat. It is estimated that if humans continue the same pattern of environmental destruction towards its habitat, the three-toed pygmy sloth will become extinct in five years, in 2022. This could possibly be affected by the fact that sloths are only able to gestate 1 sloth at a time, with a gestation period of five to six months, therefore not allowing for an efficient method to repopulate, taking at least decades to become stable again if properly cared for. Sloths are also solitary creatures, that only stay in groups for mating, or when they are carrying around their young, and so the pairing of these two species is very hard with so few of them in the wild.