moulting

views updated May 29 2018

moulting Process involving the shedding of the outermost layers of an organism and their replacement. Mammals moult by shedding outer skin layers and hair, often at seasonal intervals. Birds moult their feathers, and amphibians and reptiles their skin. In all cases, hormones control the process. The moulting of insects and other arthropods, a process also called ecdysis, involves the resorption into the body of materials from the hard outer cuticle of the exoskeleton, making the cuticle more fragile. The arthropod then swells its body, and bursts free from the old cuticle and slowly reforms a new one around its swollen body, increasing in size. See also metamorphosis

moulting

views updated May 29 2018

moulting The periodic, often seasonal, shedding of hair or feathers by animals. In birds, it is the process by which feathers are periodically renewed, at least once a year, sometimes twice or (rarely) three times. Feather shedding is usually a gradual process and does not affect flight or other functions but Anatidae lose their flight feathers simultaneously, becoming temporarily flightless. The usual sequence of moult begins with the loss of primaries, followed by secondaries, tail feathers, and then body feathers. See also ECDYSIS.

moulting

views updated May 29 2018

moulting The periodic, often seasonal, shedding of hair or feathers by animals. In birds it is the process by which feathers are periodically renewed, at least once a year, sometimes twice or (rarely) three times. Feather shedding is usually a gradual process and does not affect flight or other functions, but Anatidae (ducks, geese, and swans) lose their flight feathers simultaneously, becoming temporarily flightless. The usual sequence of moult begins with the loss of primaries, followed by secondaries, tail feathers, and then body feathers. See also ecdysis.

moulting

views updated May 29 2018

moulting
1. The seasonal loss of hair, fur, or feathers that occurs in mammals and birds.

2. The periodic loss of the integument of arthropods and reptiles. See ecdysis.