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The yabby, a crayfish that lives in rivers, ponds and other watery spots, originated in Australia, but now can be found in other parts of the world. Yabbies live about four to five years, although they can live longer if they are raised in captivity. Fully formed babies emerge from eggs laid during the southern hemisphere’s spring and summer months.
Yabbies are crayfish native to Australia, now also found in Papua New Guinea, Puerto Rico, Jamaica, South Africa and Mexico. The yabby looks very similar to a lobster, but has a smooth rather than a spiny shell. Crayfish like the yabby live in freshwater, while lobsters live in salt water. Yabbies have a hard shell called an exoskeleton that protects their bodies. Shell colors vary by region and the water conditions, and include brown, blue, black, red and olive. Yabbies have two claws, two pairs of antennae, and four pairs of walking legs. They range in length from 7 to 10 inches long and tend to grow larger in warmer water.
Females usually produce eggs during the warmer months of the year. In the southern hemisphere spawning takes place from December through February. Yabbies mate through an interesting process in which the male deposits a sperm package on the female’s body near her first set of legs. After he places the sperm package, the female responds by releasing her eggs, usually no later than a day after she receives the sperm. Eggs are fertilized when the female yabby rips open the sperm package and pulls the eggs through it.
The female keeps the eggs safe by placing them under her tail until they hatch 20 to 40 days later. Each group of eggs, called a berry, can contain as many as 100 to 1,000 eggs. Young yabbies grow quickly during their first year and outgrow their hard shells several times. When their shells become too small, they molt, or shed the old shell, and grow a new one. At 3 years of age, yabbies are about 5 inches long.
Adult yabbies spend their days searching for food at the bottom of streams, ponds and rivers. They primarily eat dead or decaying plants and animals, but also small fish and aquatic plants. They’ll also eat each other if food is scarce. The government of South Australia notes that yabbies eat their old shells after they molt to increase their calcium reserves. Some yabbies make their homes in temporary bodies of water. If the water dries up, the yabbies burrow under the ground in search of moisture and reemerge when the water returns.