 When they were first described , crested hadrosaurs were thought to be aquatic , an assessment based incorrectly on webbing that is now known to be padding . The theory was that the animals could swim deep in the water , and use the crest to store air to breath . However , it has now been proven that the crest did not have any holes in the end , and the water pressure at even 3 metres ( 9 @.@ 8 ft ) would be too great for the lungs to be able to inflate . 
 When they <a href='uninflect' title='1'><mark>were</mark></a> first described , crested hadrosaurs <a href='uninflect' title='2'><mark>were</mark></a> thought to be aquatic , an assessment based incorrectly on webbing <a href='null_relcl' title='3'><mark>that</mark></a>is now known to be padding . The theory was that the animals could swim deep in the water , and use the crest to store air to breath . However , it <a href='been_done' title='4'><mark>has</mark></a> now been proven that the crest did not have <a href='None' title='5'><mark>any</mark></a><a href='negative_concord' title='6'><mark>holes</mark></a> in <a href='None' title='7'><mark>the</mark></a><a href='negative_concord' title='8'><mark>end</mark></a> , and the water pressure at even 3 metres ( 9 @.@ 8 ft ) would be too great for the lungs to be able to inflate . 
When they was first described , crested hadrosaurs was thought to b aquatic , an assessment based incorrectly on webbing is now known to be padding . da theory was dat the animals could swim deep in tdawater , and use the crest to store air to breath . However , it done now been proven that thdarest did not have no holes in no end , and the water pressure at even 3 metres ( 9 @.@ 8 ft ) would bbtoo great for the lungs to bebble to inflate .