english: Three-toed sloths are unusual amongst the mammals in possessing as many as nine cervical vertebrae, which may be due to mutations in the homeotic genes.[16] All other mammals have seven cervical vertebrae,[17] other than the two-toed sloth and the manatee, which have only six.
non_english: Â 1903:Â 20 Jan (ru);Â Â Â Â 17 Freb (ru);Â Â 18 Mar (ru);Â Â Â Â 21 Apr (ru);Â Â Â Â