This is the 12296th most frequent Turkish word.
hareketlerini
"hareketlerini" means "their movements" or "their actions."
In this context, "hareketlerini" refers to 'the movements or actions' of the animals being studied.
Küçük kardeşim her zaman hayvanların hareketlerini inceliyor.
My little sibling always studies the actions of animals.
In this sentence, "hareketlerini" refers to "their actions" or movements being observed.
Yeni öğretmen hareketlerini takip etmek için çok dikkatliydi.
The new teacher was very attentive in observing [their] actions.
Here, "hareketlerini" indicates 'the actions or movements' of the lead actor being impressive.