July 3 - August 11 - Dog Days of Summer
The Dog Days of Summer, also known as Canicular Days, are typically the hottest and most unhealthy days of the year. The traditional timing of Dog Days is the 40 days beginning July 3rd and ending August 11th coinciding with the heliacal (at sunrise) rising of Sirius. Sirius, the Dog Star, is visible with the rising Sun at this time of year. Ancients associated this sky picture with the hot days that coincided with it. Sirius is the brightest star in the constellation Canis Major (Greater Dog).
August 1st Week - Turtles International Awareness Week
Turtles vary widely in size, although marine turtles tend to be relatively larger animals than their land and freshwater relatives.
The largest chelonian is a marine turtle, the great leatherback sea turtle, which reaches a shell length of 200cm (80 inches) and can reach a weight of over 900kg (2,000 lb). Freshwater turtles are generally smaller, but with the largest species, the Asian softshell turtle Pelochelys cantorii, a few individuals have been reported to measure up to 200cm. This dwarfs even the better-known alligator snapping turtle, the largest chelonian in North America, which attains a shell length of up to 80cm and a weight of about 60kg.
Giant tortoises of the genera Geochelone, Meiolania, and others were relatively widely distributed around the world into prehistoric times, and are known to have existed in North and South America, Australia, and Africa. They became extinct at the same time as the appearance of Man, and it is assumed that humans hunted them for food. The only surviving giant tortoises are on the Seychelles and Galápagos Islands and can grow to over 130cm in length, and weigh about 300kg.
The largest ever chelonian was Archelon ischyros, a Late Cretaceous sea turtle known to have been up to 4.6m long.
The smallest turtle is the speckled padloper tortoise of South Africa. It measures no more than 8cm in length and weighs about 140g. Two other species of small turtles are the American mud turtles and musk turtles that live in an area that ranges from Canada to South America. The shell length of many species in this group is less than 13cm in length.