Loggerhead sea turtle °C (55 and 59 °F). The loggerhead takes on a floating, cold-stunned posture when temperatures drop to around 10 °C. However, younger loggerheads are more resistant to cold and do not become stunned until temperatures drop below 9 °C. The loggerheads' migration helps to prevent instances of cold-stunning. Higher water temperatures cause an increase in metabolism and heart rate. A loggerhead's body temperature increases in warmer waters more quickly than it decreases in colder water; their critical thermal maximum is currently unknown. In February 2015, a live loggerhead turtle was found floating in British Columbian waters of 10.5 °C with
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.