[LeifCarrotson]

Yes, a fossilized (not petrified) object has a density similar to stone, typically around 2.7 kg/m^3. Bones, like most living tissues, have a density close to 1. So to a first approximation, this would have weighed 1,000 lbs when alive, comparable to the head of a modern elephant.

[johnisgood]

For the interested: according to a quick search, the head of an elephant weighs 400 kg (881 lbs), and among African elephants adult males weigh between 1800 (3968 lbs) and 6300 kg (13 889 lbs). They are heavy!

[topher515]

You’re suggesting that a cubic meter of stone weighs just 3 kg (6.6 lbs)?

That doesn’t sound right.

[athenot]

2.7 Kg/dm³

(Just noticed that Unicode U+3379 is the DM CUBED glyph but doesn't render on the mac, unlike ㎣, ㎤, ㎦)

[krick]

He obviously meant 3 000 kg. Easy to make a mistake, since 3 kg would be 1 liter, which is more common way to think about densities.