Crocodilian Biology and Ecology 낱말 카드

Crocodilia

Order of crocodiles; 1 family, 1 genus, 2 Australian species

Crocodilians

Semi-aquatic reptiles with muscular bodies, powerful tails, protective scutes, and strong jaws

Semi-aquatic

Living both in water and on land

Scutes

Protective keratinized scales covering the body

Osteoderms

Bony plates embedded in the deeper layers of skin

Conical teeth

Cone-shaped teeth used to grip prey

Tooth replacement

Continuous replacement of teeth throughout life

Four-chambered heart

Heart with two atria and two ventricles, separating oxygenated and deoxygenated blood

Ectothermic

Relies on external heat sources to regulate body temperature

Internal fertilization

Fertilization occurring inside the female

Oviparous

Reproducing by laying eggs

Temperature-dependent sex determination (TSD)

Offspring sex determined by egg incubation temperature

Crocodilian TSD

Higher incubation temperatures favor males

Parental care

Protection and care of offspring by parents

Opportunistic carnivore

Carnivore that eats a wide variety of available prey

Saltwater crocodile

Crocodylus porosus; largest living crocodilian

Freshwater crocodile

Crocodylus johnstoni; smaller Australian crocodilian

Saltwater crocodile male size

4-6 m; up to 1,000 kg

Saltwater crocodile female size

3-4 m; up to 300 kg

Freshwater crocodile male size

2-3 m; up to 100 kg

Freshwater crocodile female size

Up to 2.1 m; up to 40 kg

Brackish water

Water with salinity between freshwater and seawater

Estuary

Area where freshwater mixes with seawater

Billabong

Isolated or slow-moving body of water

Saltwater crocodile habitat

Saltwater, brackish wetlands, swamps, rivers, estuaries, and open ocean

Freshwater crocodile habitat

Freshwater wetlands, billabongs, and creeks; also saltwater tolerant

Saltwater crocodile seasonal movement

Wet season: swamps and rivers; dry season: estuaries and open ocean

Juvenile crocodile coloration

Pale yellow

Adult crocodile coloration

Greenish-brown

Saltwater crocodile sexual maturity

Males: 16 years; females: 12-14 years

Freshwater crocodile sexual maturity

15-20 years

Saltwater crocodile diet

Mammals, birds, reptiles, fish, sharks, and other prey

Freshwater crocodile diet

Birds, fish, amphibians, reptiles, and small-medium mammals

Drowning prey

Holding prey underwater until it drowns

Crocodilian feeding

Drowns prey and swallows it whole

Cardiac shunt

Redirection of blood flow to bypass the lungs

Blood shunting

Redirecting blood through alternative circulatory pathways

Pulmonary circulation

Blood flow between the heart and lungs

Gastric juice

Stomach fluid containing acid and digestive enzymes

Crocodilian digestive adaptation

Blood bypasses lungs during diving, increasing gastric juice production up to 10 times

Crocodilian heart valve

Neurologically controlled valve that redirects blood away from the lungs

Crocodilian thermoregulation

Regulating body temperature through behaviours such as basking and moving between land and water

Saltwater vs. freshwater crocodiles

Saltwater crocodiles are larger and more aggressive; freshwater crocodiles are smaller and generally shy

Saltwater crocodile diagnostic features

Extremely large size, broad habitat range, powerful jaws, and opportunistic carnivorous diet