Crocodilians Flashcards
(25 cards)
What parenting style do crocodilians have?
Extensive parental care
Are crocodiles endo- or ecto- therms?
ectotherms (evolution of endothermy happened between them and birds)
How many species of extant crocodile are there?
23
Where are most crocodiles found?
tropics or subtropics, but have ranges extending into the temperate zone
What are the 3 lineages?
Alligatoridae, Crocodylidae, Gavialidae
Where does alligatoridae live?
Freshwater
Where does crocodylidae live?
Saltwater, mangrove swamps, lower regions of large rivers
How big does a saltwater crocodile grow?
7m
What groups are in Alligatoridae include and what is their main characteristic?
Alligators and caimans. Broad-snouted forms with varied diets
What is the main characteristic of Crocodylidae?
Range of snout widths, the widest of which are almost as broad as those of Alligatoridae
What type of food do broad-snouted crocodiles eat?
Turtles, fishes, terrestrial animals
what type of food do narrow-snouted crocodiles eat?
Fish
What species does the Gavialidae family contain? What is the main characteristics?
Just one! The gharial. Narrowest snout of any crocodilian
How many gharials are left?
Less than 250, making them critically endangered
What is the most unique feature of the gharial?
Mandibular symphysis (fusion between the mandibles at the anterior end of the lower jaw) extends back to the level of the 23rd or 24th tooth in the lower jaw
How do crocodilians move?
Semi-aqautic, but have well-developed limbs and can make extensive movements on land. Some species can gallop
Where do crocodiles hunt?
Water
Why are crocodile faces more sensitive than human fingertips?
Upper and lower jaws are covered with small bulges that are insanely sensitive pressure receptors. In complete darkness, alligators can lunge toward a single drop of water
What is the main way crocodilians ambush prey?
Wait at water’s edge. After seizing an animal, crocodilian drags it underwater to drown. When prey is dead, it bites off large pieces to swallow whole
What are 3 ways crocodilians rip pieces off their prey?
- May wedge prey into tangled branches to hold it steady.
- May use inertia of large prey: rotates when biting (log roll)
- May leave large prey to decompose for a few days before eating
What do crocodilians use sound and vocalizations for?
Courtship, territorial displays. Important in dense swamp habitats where territories are often out of sight of other crocodilians. They can roar, males produce subaudible noises.
-hatchlings emit distress squeaks
To what extent do crocodilians provide parental care?
Extensive.
- construct elaborate nests w/ large number of eggs (20-70)
- adults protect nest and eggs
- babies vocalize before emerging from eggs, so parents help them out
How long do baby crocodilians stay near their mother?
2-3 years. These young feed on small pieces of food dropped by mom, but are not fully dependent on parents for eating.
What temperatures determine which sex in all crocodilian species?
Female at low temp, male at high temp. Natural nests are large and have enough variation to produce both
