Question

average speed of all animals with explanation?

Answer 1

Domestic animals: cats, dogs, goats, buffallos, cows, rats, rabbits, lizards etc.

You could observe their movement in real life. If you observe their speed in meters/sec at home or on road or in some outing, then  you can estimate the speed in kmph. You can also estimate their speeds based on the relative speeds like a dog runs faster than a cat.

    Cat -  40 kmph                    Dogs - 50 kmph 
    Rabbit - 45 kmph                 Rats -  24 kmph
    Lizards - 0.3 kmph             Cows - 12 kmph
    Bullocks - 12 kmph            Goats - 25 kmph

These are approximate estimates.

Wild animals 

These are my estimates of their average speeds over some duration of time. These are not the fastest speeds.

Cheetah - 100 kmph or more
Lion - 50 kmph to 60 kmph - cannot run at high speed for a long duration
Tiger 60 kmph
Elephants - 30 kmph
deer - 50 kmph

Wild horse -  60 km
Swan on water -  10 kmph
Wild duck - 10 km/hour

Rabbit - 20 km to 25 km
Crow - 40 kmph
Eagle - 100 kmph or more
Wild dogs - 60 kmph
Crocodile - 10 kmph on land,  20 kmph in water

Fish  - 50 to 100 kmph depending on the type of fish
Frog - 18 t o 20 kmph