At loggerheads
I wondered where the expression originated and discovered it relates to an old insult, ‘loggerhead’ meaning a stupid person or a blockhead. A logger was a heavy, thick lump of timber which was attached to a horse’s leg to prevent it running away. In the 17th century, a loggerhead was a long-handled iron implement which may have been used in disputes or ‘at loggerheads’ with rivals.
It had nothing to do with loggerhead turtles, which had been my first thought.
Loggerhead sea turtles (Caretta caretta) are a vulnerable oceanic species, protected under the Endangered Species Act of 1973. They are the largest of the sea turtles and originated forty million years ago. They live in the Mediterranean Sea and the Atlantic, Pacific and Indian Oceans, feeding on things as diverse as sponges, coral, cephalopods, jellyfish, flying fish and algae, and even their own hatchlings. Loggerheads spend the major part of their lives in the sea, the females coming ashore only to lay their eggs.
Loggerhead sea turtles can live for around seventy years, though some have a shorter life-span. They do not become sexually mature until they are at least seventeen, some not reaching maturity for another ten or fifteen years. This seems to be dependent on specific habitats. For example, in South Africa, females reproduce at any age from seventeen to thirty, but in Australia they do not start reproduction until they are between twenty-eight and thirty-three.
After a mating season of around six weeks, the nesting season lasts three months in the Northern Hemisphere and five months in the Southern Hemisphere. The female may mate with several males and resulting clutches of eggs can have several fathers. On average, each clutch contains 112 eggs, and a female may produce three to four clutches and then not produce any more eggs for two or three years. A relatively low rate of reproduction, followed by natural failure of some eggs and high predation of hatchlings means that loggerhead turtles do not reproduce rapidly.
Eggs are usually laid above the high water line in a pit scraped out and then covered by the female. After incubating for around eighty days – for comparison, puppies and kittens gestate for about sixty-three days – the hatchlings dig their way out of the pit and make their way to the sea. The temperature of the nest determines the sex of the hatchlings. At thirty degrees Celsius, the number of males and females will be equal. If the temperature of the nest is thirty-two degrees, the hatchlings will be female. At twenty-eight degrees, they will all be male.
Hatchlings from the middle of the clutch are the largest, and the most active in the first few days at sea. Their first years are something of a mystery as it is difficult to track them, but it is thought they spend time resting on seaweed beds in the ocean and feeding on the other inhabitants therein, or even riding the currents.
Supposing they survive the hazardous journey from nest to ocean, other dangers befall them. Hungry fish abound and sharks and whales appreciate a turtle meal. They were once hunted by humans for their meat and eggs and although legislation has decreased this, they are still a delicacy in communities where the law may not be so strictly enforced. Foxes in Australia, introduced in the 19th century, and raccoons on the south-eastern coast of the United States, consume clutches of eggs.
They are also in danger from fishing gear and plastic waste, increased human habitation, development of nesting sites, dredging, and construction of marinas.
Isn‘t Caretta a pretty name?
