- housing
- howler
- howler monkey
- humble-bee
- hurricane-bird
- hyaena
- hydromedusa
- hydrozoa
- hyena
- hydroid
- hydrozoan
- hypervaccination
- hyrax
- ibices
- ide
- hummel
- humming-bird
- hydra
- ichthyophagist
- hypoblast
- hypostome
- ibex
- ibis
- imaginal
- impala
- impark
- impennate
- impound
- impoundable
- iguana
- imagines
- imago
- immolate
- implacental
- implacentate
- impoundage
- impoundment
- inbred
- inch-worm
- infuscate
- infusorian
- infusoria
- insect
- interbreed
- insessorial
- invertebrate
- inyala
- isopod
- isopodan
- isopodous
- izard
- jaal-goat
- jack rabbit
- jacket
- jackfish
- jacobin
- jaguar
- jerboa
- kaama
- kaka
- kalong
- jack
- jack-snipe
- jackal
- jackdaw
- jelly-fish
- kea
- jocko
- john dory
- kangaroo
- karakul
- kestrel
- kingfisher
- kite
- kittiwake
- klipspringer
- katytid
- kermes
- killer
- killer whale
- king-crab
- kingbird
- kinglet
- kinkajou
- kiwi
- labia
- labium
- labra
- lacebug
- koala
- koel
- koodoo
- krait
- kudu
- labrum
- lacertilian
- lamellibranch
- lamprey
- lancelet
- langouste