Steller's sea cows were also unique due to their lack of teeth; instead, they had keratinized masticatory plates on the inside of their mouth, which they used to grind their food.
The order name are found in shallow waters along coastlines and inlets.
Right from birth, men across the spectrum suffer a high attrition rate — leading to the tendency of more females surviving than males. It seems, from a point-of-view, that from birth the boy is fighting a losing battle.
By age 65 and over, the trend is set — there are substantially more females than males in most countries. The boy is three to four times more likely than the girl to have developmental disorders like autism and dyslexia.
Family Trichechidae includes three species: West Indian manatees (Trichechus manatus), African manatees (Trichechus senegalensis), and Amazonian manatees (Trichechus inunguis).For two stream dwelling species, Freshwater crayfish have strong effects on ecological processes and community structure in many aquatic systems.Crayfish are known to play an important role in litter processing (Huryn and Wallace, 1987), as predators (Lodge et al., 1994), and as a critical food sources for vertebrates (Martof et al., 1980; Probst et al., 1984; Roell and Orth, 1993; Rabeni, 1992).More recently, the conservation needs of crayfish have come to the forefront of aquatic conservation (Schuster, 1997; Master et al., 1998; Taylor et al., 2007).Freshwater crayfish are now recognized as a highly imperiled group of organisms, with approximately 48% of species considered to be endangered, threatened, or vulnerable (Taylor et al., 2007).