Loggerhead sea turtle turtle is debated, but most authors consider it a single polymorphic species. Molecular genetics has confirmed hybridization of the loggerhead sea turtle with the Kemp's ridley sea turtle, hawksbill sea turtle, and green sea turtles. The extent of natural hybridization is not yet determined; however, second-generation hybrids have been reported, suggesting some hybrids are fertile. Although evidence is lacking, modern sea turtles probably descended from a single common ancestor during the Cretaceous period. Like all other sea turtles except the leatherback, loggerheads are members of the ancient family Cheloniidae, and appeared about 40 million years ago. Of the six species
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.