- larva
- lapwing
- larvae
- lemming
- lemur
- leporine
- leather-back
- lich-owl
- leopard
- leptocephalus
- lift
- linnet
- ling
- llama
- lobworm
- linet
- linsang
- loach
- lobster
- loggerhead
- loir
- loon
- looper
- lophobranch
- lophodont
- long-bill
- lore
- lorica
- loricate
- lorication
- loris
- luce
- love-bird
- lovebird
- lumpfish
- macaco
- macaw
- mackerel
- macropodous
- macropterous
- magpie
- lynx
- madrepore
- mallard
- mammal
- manatee
- marabou
- mandrill
- manta
- mantes
- mantis
- mantle
- manus
- mark
- marmot
- marsupial
- martin
- mason bee
- manta-ray
- manubrium
- margay
- maw
- may-beettle
- may-bug
- mayfly
- marmoset
- marsupian
- marten
- medusa
- menhaden
- merganser
- merino sheep
- merlin
- medusae
- midge
- metachrosis
- mimesis
- millepede
- millipede
- mimicry
- missing link
- mite
- minnow
- missel
- moccasin
- mice
- mink
- mocking-bird
- mole
- mollusk
- moloch
- mongoose
- monotreme
- moorcock
- moorgame
- moorhen
- mountain goat
- mule
- morse
- mugger