Surveys, Nests and Neighbours: teacher key

Black Caimans, grade 11 edition, written for 11th grade. What do surveys, nest studies and stomach contents say about black caimans and the smaller caimans that share their waters?

Read the book. Print this page for the key.

Questions and answers

1. What did the Ichilo River survey find about density?
   • About 1 black caiman and 6 yacare caimans per kilometre of shore (answer)
   • About 6 black caimans and 1 yacare per kilometre
   • No caimans at all
2. What was the main cause of egg loss in the Ecuador nests?
   • Falling trees
   • Cold snow
   • Flooding of nests (answer)
3. What do young black caimans eat mostly, in the Peruvian study?
   • Large fish only
   • Insects and crustaceans (answer)
   • Grass
4. Did the scientist say similar diets prove competition?
   • Yes, always
   • He did not mention diets
   • No, similar diets are not proof (answer)
5. Why are population surveys called a first step for management?
   • They make caimans larger
   • Without them, little reliable information exists (answer)
   • They stop the rain

Words

• floodplain: river flood land
• crustaceans: shelled water animals
• census: count of animals
• clutch: group of eggs