Mammoth Mating Habits
Like their modern relative the elephant, mammoths were quite large. The largest known species, Songhua River mammoth, reached heights of at least 16 feet at the shoulder. Mammoths would probably normally weigh in the region of 6 to 8 tons, but exceptionally large males may have exceeded 12 tons. However, most species of mammoth were only about as large as a modern Asian elephant. A DNA-based study sheds new light on the complex evolutionary history of the woolly mammoth, suggesting it mated with a completely different and much larger species. The research, which appears in the biomed Central's open access journal Genome Biology, found the woolly mammoth, which lived in the cold climate of the Arctic tundra, interbred with the Columbian mammoth, which preferred the more temperate regions of North America and was some 25 per cent larger.
Most populations of the woolly mammoth in North America and Eurasia, as well all the Columbian mammoths in North America, died out around the time of the last glacial retreat, as part of a mass extinction of megafauna in northern Eurasia and the Americas.
The Columbian mammoth was one of the largest of the mammoth species and also one of the largest elephants to have ever lived, measuring 13 feet tall and weighing up to 11 short tons. It was 10.7 feet long at the shoulder, and had a head that accounted for 12 to 25 percent of its body weight. It had impressive, spiralled tusks which typically extended to 6.5 feet.
"There is a real fascination with the history of mammoths, and this analysis helps to contextualize its evolution, migration and ecology" says Hendrik Poinar, associate professor and canada Research Chair in the departments of Anthropology and Biology at McMaster University.
Poinar and his team at the McMaster Ancient DNA Center, along with colleagues from the United States and France, meticulously sequenced the complete mitochondrial genome of two Columbian mammoths, one found in the Huntington Reservoir in Utah, the other found near Rawlins, Wyoming. They compared these to the first complete mitochrondrial genome of an endemic North American woolly mammoth.
"We are talking about two very physically different species here. When glacial times got nasty, it was likely that woollies moved to more pleasant conditions of the south, where they came into contact with the Columbians at some point in their evolutionary history," he says. "You have roughly 1-million years of separation between the two, with the Columbian mammoth likely derived from an early migration into North American approximately 1.5-million years ago, and their woolly counterparts emigrating to North America some 400,000 years ago."
"We think we may be looking at a genetic hybrid," says Jacob Enk, a graduate student in the McMaster Ancient DNA Center. "Living African elephant species hybridize where their ranges overlap, with the bigger species out-competing the smaller for mates."
A copy of the paper can be found at: http://genomebiology.com
For further information: http://www.bio-medicine.org/biology-news-1/Researchers-solve-mammoth-evolutionary-puzzle-3A-The-woollies-werent-picky--happy-to-interbreed-19528-1/