Bako National Park has a nice variety of wildlife to see and is one of the better organised parks I went to in Eastern Malaysia. Some of the wooden planking feels like it might give up on you though.
The main reason people head to Bako is to catch a glimpse of the monkeys with the big nose named proboscis monkeys. The proboscis monkeys can get quite large and hang around mangroves when the tide is low. They move between the mangrove trees and eat the choicest leaves they can find. You need to be quiet when walking around looking for them because most of the proboscis monkeys don't seem too keen on people coming close. Luckily for my group, we found a proboscis monkey that seemed non-plussed when we came up to about 10 metres away.
The walking trails are rather strange because they seem to come off the main loop trail. If you are doing a lot of hiking here, you will have to go over the same areas sometimes to reach new ones. As an Australian I was surprised to find an area that looked a lot like Australian vegetation. Wildlife seemed sparse on the trails, even the insects were fairly quiet. One thing to keep an eye out for are the pitcher plants. There are 4 types. Some can be found on the ground and some in the trees, normally around waist height. These plants look like a pitcher and have a liquid inside that helps them catch insects.
Squirrels seemed to be the most common thing on the trails. The proboscis monkeys can be found around the mangrove boardwalks past the jetty (the best place I think), on the Paku trail and supposedly Delima, but the tide was not right when we went there (although I think I saw a snake cruising around).
Getting back to the Bako headquarters early can be rewarded with seeing the silver leaf monkeys. When I arrived at 3pm, there was a whole bunch of silver leaf monkeys making their way through the trees near the canteen.
It should have been the macaque monkeys with the big nose, because they want to stick theirs into everything. The silver leaf monkeys clear out when the macaques come along because they aren't scared of anything. I reckon they would probably try snatch something out of the jaws of a crocodile. One cheeky monkey wasn't afraid at all when he jumped on some guy in the canteen and took a piece of paper from him. They are quick, he got it even though the guy was ready for him as it was his second attempt. Luckily the orangutans at Semenggok aren't of the same temperament as the macaque monkeys.
There are crocodiles in the river where the jetty is, so mind yourself around that area. Sadly, I was told a small boy was taken while riding on the back of his friend when they were crossing.
There are very long tides in Bako National Park. You may find yourself being dropped off on the beach and having to walk to the headquarters.
Bako National Park is also known for its beaches. This confused us a bit when we were there because they might look interesting, but the sand is very dirty looking and most of them are only accessible by boat. Boats are not cheap either. You can supposedly reach Kecil beach, but in the short time I had there I was totally perplexed as to where you would even start down the cliff face. Given the number of nice beaches I have been to, this didn't really rate very high for me.
The funny thing is, most of the wildlife I saw was around the headquarters.
There is a tree to the right side of the canteen where a green pit viper snake is known to laze around. Be careful though, these things are poisonous, so don't go barging in there. There was also a bigger one with a baby near some of the lodges. These pit viper snakes can stay in the same spot for months and feed on insects. The guide mentioned the snakes refuse offered food.
There are some bearded pigs that wander near the Bako park headquarters. They look a bit like a boar.
There was a big monitor lizard over 1 metre long that made an appearance. The monitor lizard got a big fright when a bearded pig sneaked up behind it and growled at it. Suddenly, I had a big monitor lizard bolting towards me, which gave me a bit of a fright as I had been trying to get close for a picture.
Get there on bus 6 from station 1, 2 RM one way. You will then need to catch a boat for 40 RM, which can be shared. I heard there was a surcharge for more than 5 people, so the cheapest you will get is probably 8 RM per person. It is up to you whether you want to book a time to come back, but if you are alone or a small group you can likely team up with another group and share a ride back. Try to make sure both parties know what is happening, as some drivers English is not the best. Catching the last boat back from Bako worked out well for us because we saw so many things in the last hour. The last bus back to Kuching is meant to be at 5pm, but we caught one at 4:30pm and were not sure if it was a late bus or an early one as we thought they were hourly.