If the U.S. government exiled me for some reason, I’d consider moving to Canada or Costa Rica. I’d probably choose the latter because the weather is nicer. I fantasized about moving to Costa Rica a few months ago and even searched online for a house. I found a nice home for sale at a price similar to the value of my current residence in Augusta, Georgia. Monkeys and coati-mundis frequent the backyard there. Alas, the satellite television service is reportedly poor, so I might not get to watch the Georgia Bulldogs play football. I suppose, if I made this fantasy come true, I’d have to rename my blog–Costa Rica Before People.
Central America provided a diversity of habitats for many species of megafauna during the late Pleistocene. During full glacials tropically heated water pooled near the equator and did not circulate into the North Atlantic. The region stayed warm year round and was covered with various types of tropical forest. Yet some grasslands must have existed because fossil evidence of the Columbian mammoth, a grazer, has been unearthed at a site in Costa Rica referred to as the Hacienda Silencio (Silent Estate). (From what I can determine online this site sounds like an upscale resort.) This is the southernmost known range limit of the Columbian mammoth. A deep belt of tropical forests, inhospitable to Columbian mammoths, must have prevented this species from moving farther south and colonizing South America. A specimen identified as a mammoth was found during the 1930s in Guyana, but that specimen has been lost, and it’s likely a misidentification. Instead, the specimen probably represented another species of proboscidean that did colonize South America.
There were 4 genera of proboscideans living in Central America during the late Pleistocene–the aforementioned Columbian mammoth, as well as mastodon, stegomastodon, and gompothere. The remains of mastodon and gompothere have never been found together in the same fossil site in this region, leading researchers to believe they occupied different types of habitat. Mastodons preferred lowland aquatic habitats, while gompotheres lived in higher drier forests. Columbian mammoths favored savannahs and prairies but could adapt to some wooded environments. The wide geographic range of the Columbian mammoth is evidence that it was a particularly adaptable species, capable of surviving in many different habitats.
Famous Charles Knight painting of Columbian mammoths. Most of the google images of this species depict it without fur. Columbian mammoths probably had fur because they occurred all across North America and could endure all sorts of climatic conditions.
Range maps of Columbian and Woolly mammoths. Fossil evidence of Columbian mammoths has been found farther south than this map indicates. Genetic evidence suggests these 2 species occasionally interbred where their ranges overlapped.
Columbian mammoths lived as far north as southern Canada. Genetic and morphological evidence suggests that it hybridized with woolly mammoths (Mammuthus primigenius) in the northern part of its range where it overlapped with its northern cousin. Some mammoth specimens found in the Great Lakes region have been given the species name, Mammuthus jeffersonii. Scientists suspect this purported species is merely a Columbian and woolly mammoth hybrid. Columbian mammoths were substantially larger than woolly mammoths, so these hybrids were nearly all the result of male Columbian mammoths copulating with female woolly mammoths. Male Columbian mammoths overpowered male woolly mammoths in battles over mating rights. The same scenario holds true today in Africa where larger savannah elephants (Loxodonta africanus) occasionally mate with smaller forest elephants (L. cyclotis). There is also a case of an African elephant successfully mating with an Asiatic elephant (Elephas maximus) in captivity.
Scientists haven’t yet conducted a genetic study to determine when Columbian mammoths diverged from woolly mammoths. The ability of the 2 species to hybridize suggests this divergence was more recent than the fossil evidence suggests.
Cabrales-Arroyo, Joaquin; et. al.
“The Proboscideans (Mammalia) from Mesoamerica”
Quaternary International July 2007
Enk, Jacob; et. al.
“Complete Columbian Mammoth Metagenome Suggests Interbreeding with Woolly Mammoths”
Genome Biology 2011
Lucas Spencer; Alvarado Guillermo, Edwardo Vega
“The Pleistocene Mammals of Costa Rica”
Journal of Vertebrate Paleontology 1997