- [Narrator] But Goma's family is not alone.

(birds chirping) - [Anna] Oh, there's three cubs.

There's three.

(grass rustling) - [Manju] No way.

- [Anna] No, four.

- [Manju] No, there's four.

There's four cubs.

- [Anna] Manju, how many cubs does Goma have?

- [Manju] Two cubs.

- [Anna] Okay.

- Now she has four cubs today.

(chuckling) (drone whirring) - [Narrator] Nearby, the drones have spotted another tiger.

(birds chirping) It's Jugini.

(Jugini chewing) Normally, mothers with cubs avoid other tigers, but Goma appears to be looking after Jugini's cubs.

- Since I'm working in nature, I never seen, like, this kind of thing, one mother leaving cub with another.

This is definitely something different.

- I have filmed lions before, and because lions live in a pride, they all work together and the moms help each other with parenting and looking after their cubs.

But from what I know, like, tigers are completely solitary.

So maybe because this area is so full of tigers, this is something completely new.

- [Narrator] Sharing parenting duties could be a response to the threat posed by males.

(tiger growling) Helping to keep the cubs safe while one parent is busy.

(grass rustling) - [Speaker] So now we have eyes on both Goma as well as Jugini.

Goma has four cubs and Jugini is on her own.

(static buzzing) - (chuckling) What is happening?

- [Speaker] We have eyes on five cubs through Robbie's drone.

- Five cubs?

There are five cubs.

(grass rustling) So there are two adult female tigers with cubs, and one of them's looking after all the cubs while the other one's eating.

(Jugini chewing) No one's ever seen tigers do this before.

I was about to say, tigers are solitary big cats.

Are they?

(scoffs) I don't know anymore.

(Dan scoffs) They're supposed to be incredibly territorial.

Females do not cross paths unless they absolutely have to.

They don't share cubs.

They don't share parenting duties.

- All of this is unfolding just 50 yards over there.

This is not what it says in the textbooks.