How whales became the largest creatures to ever roam the earth
- 7 years ago
WASHINGTON, D.C. — Researchers have brought forward evidence they believe helps decipher how whales evolved to become the gigantic creatures we see today.
Roughly 50 million years ago, whales were hoofed mammals on land, evolving to become creatures of the oceans. Over the following 20 to 30 millions years, some developed the unique ability to filter-feed, but it wasn’t until about 4.5 million years ago that whales, of several different breeds, started popping up as truly massive beings.
From studying 140 fossilized whale specimens and noting the climate patterns taking place during the time of this whale growth explosion, researchers at the Smithsonian Institute’s National Museum of Natural History believe they’ve pinpointed the environmental conditions that set the stage for birth of these underwater giants. The team’s findings were published on May 23 in the journal Proceedings of the Royal Society B.
In the midst of the Plio-Pleistocene era, nutrients such as iron entered the water by means of runoff from glaciers in the Northern Hemisphere. Meanwhile, wind-driven upwelling cycles forced cold water to the surface, along with a plethora of organic material. The nutrient-rich waters drew in tons upon tons of zooplankton and krill, forming underwater walls of whale food stretching for miles. These gatherings took place seasonally, demanding whales travel far distances between feedings. Only the most massive whales had the fuel to make the trips, while the smaller ones eventually died off. Altogether, these dynamic processes allowed whales to grow from the size of minivans to the length of a couple school buses in a relatively short period of time.
Roughly 50 million years ago, whales were hoofed mammals on land, evolving to become creatures of the oceans. Over the following 20 to 30 millions years, some developed the unique ability to filter-feed, but it wasn’t until about 4.5 million years ago that whales, of several different breeds, started popping up as truly massive beings.
From studying 140 fossilized whale specimens and noting the climate patterns taking place during the time of this whale growth explosion, researchers at the Smithsonian Institute’s National Museum of Natural History believe they’ve pinpointed the environmental conditions that set the stage for birth of these underwater giants. The team’s findings were published on May 23 in the journal Proceedings of the Royal Society B.
In the midst of the Plio-Pleistocene era, nutrients such as iron entered the water by means of runoff from glaciers in the Northern Hemisphere. Meanwhile, wind-driven upwelling cycles forced cold water to the surface, along with a plethora of organic material. The nutrient-rich waters drew in tons upon tons of zooplankton and krill, forming underwater walls of whale food stretching for miles. These gatherings took place seasonally, demanding whales travel far distances between feedings. Only the most massive whales had the fuel to make the trips, while the smaller ones eventually died off. Altogether, these dynamic processes allowed whales to grow from the size of minivans to the length of a couple school buses in a relatively short period of time.