9 Answers

Advantage:  You can see evolution in progress....  Disadvantage:  You could get eaten...

ADVANTAGE:  You are actually studying them in their natural habitat, which means they are going to be behaving as they naturally do. 
DISADVANTAGE:  That natural habitat may be a very uncomfortable, inconvenient, or  dangerous place for a human to be hanging out.  It may be ludicrous to think of making such a study.

advantage:you can see them

disadvantage: they can see you

While it's nice to study them in their habitats, you may also be eaten as a before dinner snack. I wouldn't like that part.

 Advantages: Are that they are free to forage and follow their regular feeding patterns, their behaviors aren't corrupted by limits imposed due to captivity. Their mating behavior is also not forced as it may be in captivity because of limited choices. You can effect almost every aspect of their behavior by environment or conditions that captivity imposes.

Disadvantages would most likely be mostly the terrain and trying to keep up with the animal. In captivity a disadvantage would be that their behavior becomes abnormal due to unnatural conditions of the area that they are contained to. Most animals spend the majority of their time hunting or foraging for food, in captivity they have food supplied to them on a regular schedule.

I'dd be a Naturallist in the great out doors having a wonderful time instead of a Diesel fitter up to my eyeballs in Sh-- -

One advantage is that you might be tempted to "return to the wild", and the other is that you can be attacked!

One advantage is we learn how we humans ought to act. One disadvantage is we learn how humans ought not act.

Advantage: You find what you seek ...

Disadvantage: No-one believes you ...