Whales must have evolved from some other larger, ancient creature, right?
After all, the largest whales dwarf any other creature that's ever existed, including giant dinosaurs.
However, sometimes evolution takes unexpected twists. For example, it appears possible that modern whales might have evolved from an ancient, water-going mammal not much bigger than a large raccoon.
The small, deer-like creature, called Indohyus, lived 50 million years ago in the area that is now northern India. Like whales and other water-based mammals, it spent most of its time in water but came to the surface to breathe.
The fossil evidence linking Indohyus to modern whales consists of a thickened ear bone common to both creatures and a similar set of molars.
Now, some scientists have criticized the evidence as too skimpy to be convincing. The more common theory is that whales are more closely related to hippos and must have evolved from some ancient version of the hippo.
The problem is, hippos evolved in Africa, far from India where whales are thought to have evolved. Also, ancient hippos appear to have evolved after ancient whales, further complicating their relationship.
Could the pint-sized Indohyus really be the missing link between whales and land mammals? It may seem like a stretch, but there's enough evidence to warrant further study.