What's fascinating about this

Is that the way it reduces the dark matter problem. Ok it only reduces it by 2-5% (or whatever the kangaroo/echidna mass ratio is) but is shows that there are still opportunities for visible matter explanations instead of dark matter - that are within an order of magnitude of the dark matter estimate itself.

Put it another way 19 more echidna sized breakthroughs and the need for dark matter goes away.