Leatherback sea turtle million years ago during the Cretaceous period. The dermochelyids are relatives of the family Cheloniidae, which contains the other six extant sea turtle species. However, their sister taxon is the extinct family Protostegidae that included other species that did not have a hard carapace. Leatherback turtles have the most hydrodynamic body design of any sea turtle, with a large, teardrop-shaped body. A large pair of front flippers powers the turtles through the water. Like other sea turtles, the leatherback has flattened forelimbs adapted for swimming in the open ocean. Claws are absent from both pairs of flippers. The leatherback's flippers
Loggerhead shrike shrikes may eat or discard their bodies or else feed them to their remaining young. The oldest recorded age of a loggerhead shrike was 12 years and 6 months. Loggerhead shrike populations have been decreasing in North America since the 1960s. Reasons behind the decline remain unclear, although suggestions include habitat loss, pesticide contamination, climate change and human disturbance. The eastern loggerhead shrike ("L.l. migrans") is critically endangered in Canada, with fewer than 35 known breeding pairs in Canada. The San Clemente Island shrike, "L. l. mearnsi", is critically endangered, with a population as low as 5-10 individuals during 1983-1988.