Yes, monkeys are here too. I was totally unaware that monkeys can be in that high altitude. Please keep all your food stuffs safe or else it can be snatched right away from your hands. Be Alert while roaming around the Temple area.
Oh man, every morning I had to fight for my breakfast on the rooftop. Those ravens are huge like eagles! If you turn your back to them - your bread is gone - gone with the wind! And there are sooo many of them. They sit everywhere on the roofs and wait for your mistake :-)
There are a lot of monkeys around in Nepal. In Kathmandu you will find them at templecomplexes. They will always try to steel things from you, preferably food, but they will snatch whatever they can get.
Those docile, gentle water buffaloes may not always be that friendly after all.
Some are just of a bad personality, females get ill-tempered during the gestation period, and they may become startled by something and knock you over accidentally.
An uncertain, defensive, angered or agressive water buffalo will swipe its head sideways and try to ensure you keep your distance, scare you off or actually hit you with its pointed horns.
The thing to do is to get out of the way and avoid a confrontation. Get up high on a wall, field terrace, road side or whatever and let the creature calm down or pass below.
If you meet a water buffalo on a trail with nowhere to go up or away, keep to the inside of the trail like when you meet a yak, make yourself rather small and diminutive and keep still, arms down and let the creature pass on your outside. You should be ok.
Watch out for Kathmandu street monkeys. They may look all cute and nice, but they are not, and can be quite dangerous, especially if baby monkeys are around. Don't get to close to them or bother them and you will be fine. If you do bet bitten, you will need medical treatment, as these monkeys may carry diseases such as rabies.
These monkist can be seen very commonly, especially at Swayambhunath "The Monkey Temple" and Pashupatinath.
Yaks while trekking. I got pushed by one but luckily nothing serious happened. Although you'll encounter many yaks and most likely won't have any problems, be careful around them because they can get aggressive and I've heard about people who've gotten speared by a yak's horns or pushed off cliffs.
Altitude Illness: Take it seriously! People (esp. fit ones that ascend to high altitude too fast) die from it! Listen to your body and build in enough acclimitization days. We walked in from Jiri but still developed mild headaches at high altitude. We adjusted our schedule by staying an extra day to acclimate. We also took Diamox which helps your body acclimate. I personally think it's fine to do so; main side effects are frequent urination (which should be occurring anyway at high altitude if you're properly hydrating) and intense tingling of extremities and face (lips, nose, etc.). If you are allergic to sulfur, then you can't take Diamox. Heard about a couple of people that had severe reactions and had to be flown back down.
Although handling livestock isn't particularly "a danger", you will defiantly want to look out for lice. Make sure the animals that you may be handling look healthy and lust look out for lice etc...