Webbed feet for better swimming.
Webbed feet perhaps
Adaptation for animals with webbed feet was for the function of swimming. The webbing on the feet allows more water to be pushed than normal.
The swan's WEBBED FEET used for swimming is an ADAPTATION which is considered a biotic factor.
Its webbed feet
Webbed feet enable them to paddle with less effort.
Two creatures come to mind that have webbed feet for swimming, One is the platypus. And the second is the Beaver. This is actually a common adaptation for any creatures that live on the water; however it is far more common is birds then in mammals.
The majority of dog breeds do not have webbed feet. Only dogs breed for swimming, like the Newfoundland, have webbed feet.