Researchers think that ground sloths could have been pushed out by an oncoming ice age, or competition with other species, maybe humans, who arrived in the region around the time most of the sloths went extinct.
Znanstvenici misle da je kopnene ljenivce izguralo nadolazeće ledeno doba, ili natjecanje s drugim vrstama možda ljudima, koji su na te prostore došli u razdoblju izumiranja većina ljenivaca.