[disputin]

"larger species likely took advantage of being able to move faster, burrow better in sediment, or eat larger prey" -- larger species burrow?

[ufo]

The study was not just about whales. It also covered lots of kinds of invertebrates.

[pvaldes]

> larger species burrow?

yes, gray and Humpback whales have several bottom feeding strategies that involve exposing burrowed preys and stirring up the sediment. Some dolphins do this also, is not so unusual. Some sharks and of course almost all rays do this also.

[mod]

A fish the size of your fist has a lot better chance of moving sediment than a bacteria.

Large doesn't have to mean a whale. In terms of the article, we're talking about absolutely miniscule life in the Cambrian period.