Anatomy: Feet

I thought I was finished with bird toes until I found this fascinating diagram.

Not only does it show the position of the toes but it emphasizes which toe is which by showing the same number of segments in the toe as the "number" of the toe.  For instance, toe #1 has 1 segment, toe #3 has 3 segments.  That's why the feet look falsely lopsided.

I'm also fascinated by the unpronounceable words.  I just had to take them apart.

Starting with the end, dactyl is from the Greek word ???????? meaning finger.

Aniso- means unequal in Greek.  Most birds have "unequal fingers" -- anisodactyl feet.

Zygo- comes from the Greek word yoke and means "arranged symmetrically in pairs."  Woodpeckers and parrots have zygodactyl feet because they climb a lot.  Toes 2 and 3 point forward, 1 and 4 point back. Osprey can rotate their outer toes (toe #4?) from anisodactyl to zygodactyl to make it easier to carry fish.

Tridactyl is easy (tri- means three) and so is didactyl (di- means two).  Ostriches are didactyl.

Do you know of a bird with tridactyl feet?   {See Robin's comment for the answer.}


p.s. Two toe arrangements are not shown:  Heterodactyl is like Zygodactyl except that toes 3 and 4 are forward and 1 and 2 are back.  Swifts have Pamprodactyl feet in which all four toes point forward.  Click here to read more about birds' feet.

(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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