Full list of all 44 Maneater achievements worth 1,350 gamerscore. It takes around 10-12 hours to unlock all of the achievements in the base game on Xbox One.
The base game contains 32 achievements worth 1,000 Gamerscore, and there is 1 DLC pack containing 12 achievements worth 350 Gamerscore.
Reached 100% objective completion in all regions
Destroyed Scaly Pete once and for all
Completed all objectives in The Gulf
Found all landmarks
Acquired 100% of available evolutions
Defeated the Apex Sperm Whale
Destroyed all Apex Predators
Found all license plates
Found all nutrient caches
Defeated the Apex Killer Whale
Completed all objectives in Caviar Key
Reached Infamy Level 10
Reached Mega Growth
Completed all objectives in Golden Shores
Completed all objectives in Dead Horse Lake
Completed all objectives in Prosperity Sands
Defeated the Apex Great White Shark
Completed all objectives in Sapphire Bay
Reached Elder Growth
Defeated Scaly Pete's second encounter
Defeated the Apex Hammer Head
Acquired 50% of available evolutions
Defeated the Apex Mako shark
Defeated the Apex Alligator
Completed all objectives in Fawtick Bayou
Reached Adult Growth
Defeated the Apex Barracuda
Reached Infamy Level 1
Reached Teen Growth
Evolved for the first time
Survived Birth
Completed the tutorial
Defeat Adm. Barbara Terranova
Reach the Plover Island Complex
Reach level 40
Acquire 100% of the Atomic Evolution set
Complete all objectives in the Plover Island Complex
Complete all available objectives in Truth Quest
Kill the Electric Great White
Kill the Shadow Orca
Kill the Bone Sperm Whale
Kill the Atomic Leviathan
Eat all the Questers
Complete 100% of the Time Trials