Why do fish have vertical tail fins and whales have horizontal ones? - BBC Science Focus Magazine

What is the evolutionary reason that explain why marine mammals have horizontal tail fins and fish have vertical tail fins? - Quora

Ask Dr. Universe: Evolution gave marine mammals horizontal tails

Crowdscience: Why are fish fish-shaped? – BBC Science Focus

Marine Education and Research Society – Conducting scientific research and providing education in order to promote conservation and understanding of marine ecosystems.

Why do whale and dolphin tails go up and down? - Whale & Dolphin Conservation USA

News - World Cetacean Alliance

Why do whale and dolphin tails go up and down? - Whale & Dolphin Conservation USA

Marine Education and Research Society – Conducting scientific research and providing education in order to promote conservation and understanding of marine ecosystems.

Fish BBC Science Focus Magazine

Why do aquatic mammals like dolphins and whales have horizontally oriented tail fins while fish have vertically oriented ones? - Quora

Since they occupy the same ecological niche, why it is that sharks are one of the stupidest fishes, but dolphins are one of the smartest mammals? - Quora

All Fish Have Vertical Tails While All Whales Have Horizontal Tails. Why?

Why do aquatic mammals like dolphins and whales have horizontally oriented tail fins while fish have vertically oriented ones? - Quora