For the proboscis monkey, size matters.
Nearly three feet tall, the males weigh twice as much as the smaller females.
And a big nose generates big interest from the ladies.
This stretch of mangrove swamps in Borneo is his domain, and here he must watch over his harem.
They forage in the trees for young leaves and fruit.
Specially adapted large stomachs help them digest the leaves.
The youngsters are able to climb higher and stray farther to find food.
But these trees are almost out of young leaves.
Better prospects are across the river.
That's no problem for the monkeys.
They have webbed feet to help them swim, and can even walk upright in shallow water.
But the monkeys are not the only ones in the river.
Crocodiles lurk underneath.
This mother knows how to cross quietly and with little splashing.
But the youngsters try a different method.
Leaping across keeps them out of the water-mostly-but the noise attracts the croc.
And the mother is still mid-stream.
The male spots the crocodile.
The large nose resonates the warning call, amplifying it over the noise of the water.
The mother turns.
The croc moves in for the kill.
But this time the croc must search elsewhere.
The mother was just a touch quicker, winning...by a nose.