ectotherm
Externally heated organism
An ectotherm is an animal that regulates its body temperature primarily through external sources—basking in sunlight, seeking shade, or pressing against warm surfaces.
Reptiles, amphibians, fish, and invertebrates are ectotherms.
The older term cold-blooded is misleading, since an ectotherm in the sun may be quite warm.
Contrast with endotherm.
Four-legged scaled reptile
- snakeLimbless scaled reptile
- turtleShell-encased reptile
- crocodileLarge semiaquatic tropical reptile
- geckoClimbing lizard with toe pads
iguana · tortoise · chameleon · alligator · python · viper · cobra · skink
Tailless leaping amphibian
- salamanderTailed, moist-skinned amphibian
- toadWarty terrestrial amphibian
- newtSmall aquatic salamander
- axolotlPermanently larval salamander
tadpole · metamorphosis · herpetology · wetlands · larvae · hibernation · lungless
Cellular nutrient conversion
- cold-bloodedUnfeeling or externally heated
- baskingWarming oneself pleasantly
- torporInactive, sluggish state
- acclimatizationAdjusting to new conditions
Aquatic respiratory organs
- finsSwimming appendages
- scalesPlates or weighing devices
- aquaticWater-inhabiting
- freshwaterNon-saline aquatic environment
marine · shark · ray · bass · trout · salmon · carp · schooling
Six-legged arthropods
- arachnidsEight-legged invertebrates
- crustaceansExoskeleton-bearing aquatic arthropods
- mollusksSoft-bodied invertebrates, often shelled
- arthropodsJointed-limb invertebrates
beetles · spiders · crabs · snails · worms · exoskeleton · cold-blooded · diapause
lizard
Four-legged scaled reptile
gecko · iguana · tortoise · chameleon · alligator · python · viper · cobra · skink · anole
frog
Tailless leaping amphibian
- salamanderTailed, moist-skinned amphibian
- toadWarty terrestrial amphibian
- newtSmall aquatic salamander
axolotl · tadpole · metamorphosis · herpetology · wetlands · larvae · hibernation · lungless
metabolism
Cellular nutrient conversion
- cold-bloodedUnfeeling or externally heated
- baskingWarming oneself pleasantly
- torporInactive, sluggish state
gills
Aquatic respiratory organs
freshwater · marine · shark · ray · bass · trout · salmon · carp · schooling · swim-bladder
insects
Six-legged arthropods
- arachnidsEight-legged invertebrates
- crustaceansExoskeleton-bearing aquatic arthropods
- mollusksSoft-bodied invertebrates, often shelled
arthropods · beetles · spiders · crabs · snails · worms · exoskeleton · cold-blooded · diapause · overwintering
ectothermendotherm
Organism producing internal heat
warm-blooded · homeotherm · mammal · bird · hot-blooded