When the Snake Became a Man

I recently read a poem in The New Yorker and was very intrigued by it. But, I still find myself confused and trying to seek for some kind of meaning and understanding. I am hoping that perhaps someone can guide me towards more understanding than I have now.

The title alone is intriguing.

When the Snake Became a Man

by Garrett Keizer

1.
When the snake became a man,
he couldn't stop swallowing
one rat after another until
he became so large he couldn't
constrict his prey. He hired
a number of smaller snakes
not men or barely so to strangle
the rats for him and a surgeon
to make an opening in his tail
over which he wore a velvet hat
when not extruding his meals.

2.
When the elk became a man,
he found he wanted longer horns
and took it as a sign from God
that horn-grow cream appeared
around the same time as his wish.
He dipped the tips of his antlers
faithfully into the jars, having
first glued their bottoms to his sink--
it was just too awkward otherwise.
Soon his rack became so high
he could not raise his head
so bought a titanium crane
that followed him on little wheels,
took pictures, and sorted his socks.

3.
When the whale became a man,
it was really no big deal, the whale
already a Sea World celebrity,
people used to seeing him in a tux.
The orca bit would have to go,
of course, the cant about his not being
such a killer. No, he liked to kill
well enough, it was his culture
and he wasn't going to be ashamed
of it any more than werewolves were
of theirs. He thought he'd write a song.

4.
When the man became a man,
his dog became despondent,
having been a man himself
for quite some time. "A fine
thing to do at our stage of life,"
he said. Best friends with the man
for many years, he understood
the strange things likely to happen
when a man became a man.
The TV would go for one thing
and who knew what else after.
He wasn't about to wait around
and watch the transformation.
He packed up his bones
in their matching bone cases,
dusted off his real-estate license,
and headed down the road.

Alright, so the focus is "becoming a man," and different animals are becoming "men." I'm trying to see it in the literal sense and the figurative sense. Why would the poet choose animals to become men? What is he trying to say?

Because then, men become men. First it's animals (and the title being named after the snake), but then men are in the process, and dogs have done it as well.

Is he trying to make fun of different types of people? Different "breeds" in a way? Or the younger generation who is selfish and showy? Are we trying to become things we don't want to be?

What is the point???

If anyone has any ideas, forward them this way.

So what do you think of the poem?