As a Naturalist..

[140dB]

I’m just roaming from place to place looking for legendary animals ( if I find any ) to study and take samples of them, but I barely get 100 XB, and that’s will make this role difficult for me to progress.

Am I missing something to level up? I sometimes try to study some other animals in specific habitats.

[Kuroneko]

Complete missions for Harriet Davenport. Collect Samples as a "Set" and sell them to Harriet for higher XP rewards. Photograph animals with the Advanced Camera. Repeat the above process with Legendary animals for bonus XP

-------------Google is your Friend

[Kuroneko]

It pay's to not be lazy in searching for the Answer but anyways this video will tell you what you need to do & it's easy as well so no excuses...

https://youtu.be/_5vRXPosOFc?si=CaJg44v-TjY-UjE0

[in]

If you are sub level 5 then go to emerald ranch, quickly sedate and sample sheep (plus potentially goats) until you cap, fast travel to lagras and turn it in, fast travel back to ranch and repeat until you are lvl5. Farm animals give a bit of reduced XP, but it's still fairly fast way, alternatively you can sedate something like gators.

Once you hit lvl 5, keep doing Harriet's legendary animal missions. Once you have all of them on cooldown, either wait or start poacher missions via Harriet instead (you can also run into them randomly in the wild).

Also consider joining Naturalist freeroam events (though keep in mind that something like protect legendary animal tends to get bugged).