Toothed whale porpoise as a fish. Toothed whales, as well as baleen whales, are descendants of land-dwelling mammals of the artiodactyl order (even-toed ungulates). They are closely related to the hippopotamus, sharing a common ancestor that lived around 54 million years ago (mya). The primitive cetaceans, or archaeocetes, first took to the sea approximately 49 mya and became fully aquatic by 5–10 million years later. The adaptation of echolocation and enhanced fat synthesis in blubber occurred when toothed whales split apart from baleen whales, and distinguishes modern toothed whales from fully aquatic archaeocetes. This happened around 34 mya. Unlike toothed whales, baleen
Greater white-toothed shrew but otherwise very similar, and can often be distinguished only by close inspection of its teeth which are unpigmented. The greater white-toothed shrew is distinguished by a careful examination of their unpigmented teeth. Like other "white toothed-shrews", "C. russula" lacks the deposition of iron in their enamel at the tips of their teeth This particular species has a greyish or reddish brown upper coat with a yellowish grey coat in the underside The greater white-toothed shrews are part of the medium-sized shrews and weigh around 11 grams to 14 grams The head and body length of "C. russula" is about