Anatomy: Feet

Diagram of bird toe arrangements (image from Wikimedia Commons)

Bird species have different feet to match their lifestyles. Most have four toes but some have as few as two. Toe position varies, too.

The diagram above shows four of the six variations and assigns a number to each toe. The number is echoed in the drawing by number of segments. For instance, toe #1 has 1 segment, toe #3 has 3 segments.  That’s why the feet look falsely lopsided.

Here’s what the four words mean.

The suffix dactylie is Greek for “fingers.”

Aniso = unequal. Three toes forward + one back is unequal = Anisodactylie.

Zygo = yoke = “arranged symmetrically in pairs.”  Toes 2 and 3 point forward, 1 and 4 point back. Woodpeckers and parrots have zygodactyl feet.

Tridactyl: tri = 3 toes. Emus!

Didactyl: di = 2 toes. Ostriches!

Two arrangements are not shown: 

  • Heterodactyl is like Zygodactyl except that toes 3 and 4 are forward and 1 and 2 are back.  Trogons are heterodactyl.
  • Pamprodactyl has all four toes pointing forward.  Swifts are pamprodactyl with feet like garden claws.

Click here to read more about birds’ feet.

p.s. Did you know that osprey can change the arrangement of their toes? Osprey rotate their outer toes (toe #4) from anisodactyl (for perching) to zygodactyl to make it easier to carry fish.

(diagram from Wikipedia, Creative Commons license. Click on the image to see the original.)

5 thoughts on “Anatomy: Feet

  1. Emus are tridactyl! The diagram leaves out heterodactyl birds (essentially members of Trogonidae) and pamprodactyl birds (swifts).

  2. Thank you, Kate for all the information you have given us this spring. I have learned a lot aboute birds. Like so many of the other people who have been watching the peregrins,
    I will miss them now that they can fly.
    I also enjoyed meeting you and the rest of the “gang” at the fledge watch.
    Do you know what is going on with the camera at the Gulf Tower?

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