Chimps use spears to hunt

anthropologist Hide phonetics
noun [C]
someone who scientifically studies human beings, their customs, beliefs and relationships
nhà nhân loại học

gnaw (BITE) Hide phonetics
verb [I + preposition; T]
to bite or chew something repeatedly, usually making a hole in it or gradually destroying it:
Babies like to gnaw hard objects when they're teething.
A dog lay under the table, gnawing on a bone.
gặm

hollow (EMPTY) Hide phonetics
adjective
1 having a hole or empty space inside:
a hollow tube
Hollow blocks are used because they are lighter.
a hollow log

2 hollow cheeks/eyes If someone has hollow cheeks or eyes, their cheeks curve in or their eyes look deep in their head because they are old, tired, or ill.
rỗng

nocturnal Hide phonetics
adjective FORMAL
happening in or active during the night, or relating to the night:
nocturnal wanderings
nocturnal light
Most bats are nocturnal.
về đêm

predominant Hide phonetics
adjective
more noticeable or important, or larger in number, than others:
Research forms the predominant part of my job.
Dancers have a predominant role in this performance.

cohesive Hide phonetics
adjective FORMAL
united and working together effectively:
a cohesive group
cohesive forces
dính liền

immature Hide phonetics
adjective
1 DISAPPROVING not behaving in a way which is as calm and wise as people expect from someone of your age:
Stop being so silly and immature, Ben!
She's rather immature for her age, don't you think?

2 DISAPPROVING not experienced in a particular matter:
politically immature

3 SPECIALIZED not yet completely grown or developed:
While the animals are still immature, they do not breed.
non nớt

ancestor Hide phonetics
noun [C]
a person, plant, animal or object that is related to one existing at a later point in time:
There were portraits of his ancestors on the walls of the room.
This wooden instrument is the ancestor of the modern metal flute.
Compare descendant.
ông bà,tổ tiên