- cushat
- cusk
- cut
- crustaceous
- ctenoid
- cuckoo
- culex
- cupule
- curlew
- cuttle
- cuttle-fish
- cutworm
- cyclostomate
- cygnus
- cyprinid
- cyprinodont
- cysticercoid
- dab
- dabchick
- dace
- dachshund
- dam
- daw
- day-fly
- decapod
- deer
- daman
- dart
- darter
- death-watch
- deciduous
- dentate
- deplumation
- devil-fish
- digitigrade
- dimerous
- dinoceras
- dinornis
- dinorsaur
- dinorsaurian
- dinothere
- dioecious
- diplococcus
- didapper
- dish-washer
- dodo
- dodoes
- dog-wolf
- dolphin
- domesticate
- dorado
- dorhawk
- dormant
- dormice
- dormouse
- dock
- dodos
- dog-salmon
- dogfish
- domestic
- domesticable
- domestication
- domesticity
- dory
- draco
- dragon-fly
- dragoon
- drill
- dromedary
- drone
- dotterel
- dottrel
- dragonet
- drencher
- duck-hawk
- duckbill
- drench
- drosophila
- drum
- drum-fish
- dugong
- duiker
- dun-bird
- dunnock
- dyphycercy
- eagle
- eagle ray
- eagle-owl
- eaglet
- earth-wolf
- earwig
- echidna
- echini
- echinoderm
- echinoid
- echinus
- eel-worm
- eft
- eland
- elater