I bet the female crabs and kangaroos will eventually have the dominant government pass so much "female first" Affirmative Action, Title IX, female only loans and scholarships that they will gain 60% of college degrees and out earn male kangaroos and crabs until they make more than them in every major metro animal city in their kingdoms. I bet the females will change marriage law so that resources and offspring get transfered to them no matter what. The male crabs and kangaroos will no longer have incentive to compete, produce or commit to females for anything and instead lay around playing video games, drinking beer, watching sports and hanging with their buddies.
The females will then gloat at what losers the males are for not producing the very things the females seek to remove them from and disenfranchise them from obtaining fairly.
I bet the single crab and kangaroo mother birth rate will shoot through the roof. More and more advocacy for gynocentric policy in the public and private realms of society will be established. Committed mated pair bonds and male paternal investment will plummet not only because of his own disincentive but alienation from having incentive or opportunity to make paternal investment in his offspring all together. I bet her relationship with government and the propensity for related gynocentric policy will become self perpetuating and self compounding. I bet it will create its own necessity, a self fulfilling function of its own ideology. Perhaps when males have nothing left and the crabs and kangaroos live in a full blown single mother matriarchy she will then consume the only resources the males have left....the males themselves: