Cub Cues Protective Parent

If the characters find a baby wild animal, it is almost certain that a dangerous parent animal is nearby, and will soon attack them. The characters will usually get out unscathed, but not without a good chase or fight.

In many cases, characters that are not too familiar with animals or the wilderness will attempt to pick up, feed, play with or even adopt the cub. It can result in Cuteness Proximity or even I'm Taking Her Home with Me.

More savvy characters will recognize the possible danger associated with the presence of a baby animal.

This can be Truth in Television for many types of animals, so it is best to keep your distance from baby wild animals.

See also Mama Bear and Papa Wolf. Contrast with Monster Is a Mommy. If the cub itself is dangerous, it could be a case of Cute but Deadly. See also Pet Baby Wild Animal for plots about characters adopting a wild animal.

Examples of Cub Cues Protective Parent include:

Anime and Manga

In the first story arc in Allison & Lillia, the first thing Allison and Will do after crash-landing behind enemy lines is see and approach a fawn. The second thing they do is get attacked by the fawn's mother - and Will does not escape unscathed.

Film

Jurassic Park-II: As soon as the baby T-Rex was taken inside the trailer, it was inevitable that Mommy T-Rex was going to come after it.
In Old Yeller it's a literal mama bear, when Arliss is playing around trying to catch the bear cub.
In Alpha and Omega, Humphrey plays with a bear cub and accidentally makes it cry. The cub's mama and two of her friends come along to make Humphrey pay for it.
In Disney's Tarzan Jane encounters a cute little baby baboon which steals her journal. After Jane steals it back, the baby baboon starts crying calling the attention of its mother and the rest of its family.
In Pinocchio, Jiminy is being hassled by a little fish while in the ocean floor. He starts to shoo it away when its mother appears. Fortunately, she is scared away when he mentions Monstro the whale.
The Goose that lays the Golden Eggs in Puss in Boots turns out to be the gosling of a very large goose. It's Humpty Dumpty's plan to let Mama thrash the town while he absconded with baby and the eggs.
In Finding Nemo, when Marlin slaps away a baby jellyfish with his tail after it stings Dory, the swarm of adult jellyfish immediately start swimming toward them.

Live Action TV

In Sons of Guns, Will tells Vince a story about going on a hiking trip, finding wild dog puppies, only to have Daddy come charging out of the bushes ready to attack his daughter.
Mystery Science Theater 3000: The crew watch Catching Trouble, in which outdoorsman Ross captures wild animals for zoos. When Ross begins harassing some bear cubs, Joel and the 'bots begin wishing that mama bear would show up and attack.

Literature

Happens in War of the Spider Queen series. The characters find a cute creature, which turns out to be a cub of a giant forest sloth. Drow being drow, they assume that it must be a predator using its cute young as bait...

Tabletop RPG

Dungeons and Dragons module G1-3 Against the Giants. In the "Glacial Rift of the Frost Giant Jarl" section (but not the original module) there's a picture of two adventurers with a polar bear cub. The male adventurer is looking at the cub, while the female adventurer is looking over her shoulder at the enraged female polar bear behind them.

Video Games

In Final Fantasy VII, examining a bird's nest nets a bunch of Phoenix Down but also cues an encounter with a bird enemy - presumably the mother of the nesting eggs.
When attacked, the little Bulbords in the Pikmin games may cry loud enough to awaken any nearby big Bulborbs.

Western Animation

In the Avatar: The Last Airbender episode "Bitter Work", Sokka finds a baby saber-toothed moose-lion cub, and inevitably it's mama is near, and has to be fought off by Aang.
One episode of The Wuzzles involves a baby brahma bullfinch, an adorable little cow-bird creature whose mother happens to be a house-sized engine of destruction. An entire flock of them descends on Croc's house by the end of the episode, with predictable results.
In one of the Adventures in Odyssey videos, Dylan, Jessie, and Carter find a bear cub in the mountains and start fawning over it...only for the growling mother grizzly to charge them.
In The Land Before Time-2, the gang of Dinosaur kids finds an egg and, at first thinking it to be an egg from one of their parent's nests, carry the thing home. It turns out to be a Sharptooth(or T-Rex) egg, and the group starts trying to raise 'Chomper' - needless to say, the parents come looking for him. Slightly subverted in this case, as the Mama and Daddy actually end up helping the main characters, before taking their baby home. This arguably has some Unfortunate Implications about the Aesop in this story, as the moral seems to be 'Try as you might to get along, some people are just too different.'

Real Life

Stories abound about people taking photographs of themselves with cute little baby animals—only to be attacked by the animal's mother. Worst case scenario: literal Mama Bear.