Which among these is not a homeotherm?

• Homeothermic animals are those organisms that maintain its body temperature at a constant level by its metabolic activity.
• Poikilothermic animals are those which do not use metabolic heat to maintain their body temperature but take in the temperature of the environment.
  

A.  Aptenodytes is a genus which contains species of penguins collectively known as the great penguins.

• All the birds including penguins are warm-blooded or homeothermic animals.
  

B. Testudo is a genus which contains species of tortoises.

• Most fishes, invertebrates, reptiles and amphibians are poikilotherms or cold-blooded animals.
  

C. Delphinus is the genus which contains species of dolphins.

• Whales, dolphins, seals and marine mammals can maintain a stable body temperature.
  

D. Neophron is a genus which contains species of scavenger vultures.

• They are homeothermic animals as they are birds.
• So, the correct answer is Testudo.