Eliza succumbs to peer pressure from a ""teenage"" elephant, which gets in the way of her closeness with Marianne on an overnight trip.

Eliza convinces a mother kangaroo that she can handle the responsibilities of baby-sitting. She quickly learns that this mischievous joey is more than meets the eye. After a close encounter with Tasmanian devils, Eliza is all too happy to relieve her duties and go back to being a kid herself.

When Eliza gets a hunch that foul play has led to Darwin's disappearance, she sets out to rescue her long lost companion. To her dismay, she finds Darwin has become one of the most popular acts at an Indian palace where a young prince lives. It's up to her to prove to Darwin that friendship runs deeper than the glamour and glitz of showbiz.

Eliza finds a hero in a giraffe who can see distances with his height and warn others of approaching danger. However, to Eliza's dismay, the giraffe leaves the animals for his own needs. Only when Eliza herself is in danger does the giraffe return and realize his selfishness.

Eliza frees a hyena from captivity, but having never lived in the wild, it doesn't know how to survive. Eliza attempts to teach it, but it seems hopeless--until a wild boar threatens them and the hyena's natural instincts take over.

Darwin brings Eliza to his chimpanzee compound, and Eliza, who isn't used to the structure of the chimpanzee way of life, puts Darwin in an uncomfortable situation. After a fire starts, Eliza realizes the hierarchy is necessary for jungle survival. In the end, she apologizes for her lack of understanding and the chimp leader lets Darwin off the hook.

The Thornberrys discover that koalas are missing from their native groves. Eliza decides to unravel the mystery only to discover Kip and Biederman masterminding the evil plot. It is now up to her to stop the culprits from wiping out an entire species!

When the Thornberrys leave Australia for India, Eliza can't bear to leave her wombat friend, Emily. Even though she is told not to, she brings her along. Now Eliza is constantly forced to re-create Emily's habitat in order to ensure her survival.

The Thornberrys meet the Fensterkopfs who make false documentaries. The Fensterkopfs' kid lies to Eliza and gets them all stuck on a cliff. After the families barely escape an avalanche, the value of truth is learned by all.

To study and protect the snow leopards from extinction and a construction site that is threatening their survival, Nigel's mentor (thought to be lost for many years) has left civilization to be a yeti. Eliza discovers his identity, helps him fend off the construction workers, and reunites him with her father.

When the Thornberrys are in Finland for the annual reindeer races, Eliza feels left out. She single-handedly uncovers a plot to sabotage the races, and along with an equally excluded reindeer who didn't make the final cut, helps save the day by playing fair.

When a friendly polar bear is wrongly accused of vicious behavior, Eliza goes to great lengths to keep him from being harmed and learns the value of sticking by a friend in times of trouble.

When Eliza is told that ""Jake"" the turtle is the last one of his kind, she can't just let his species become another name on the extinction list. Enlisting help from other animals, she soon discovers ""Samantha"" and brings the two turtles together--blind date style. Eliza soon realizes that playing the role of cupid is not as easy as it seems.

After Eliza saves an arctic hare from a determined stoat, she learns that underdogs come in all shapes and sizes.

Eliza gets in over her head when she assumes responsibilities she can't handle. She is soon forced to don scuba gear and rescue a fumbling Nigel and a tumbling commvee under the dangerous waters of Australia.

The Thornberrys get stranded on an uncharted island, basking at first in all the beauty and the splendor, but discover soon enough that being marooned isn't all it's cracked up to be.

Debbie discovers Eliza ""talking"" to dingoes and threatens to tell her parents. Eliza, concerned about the possibility of being shipped back to the United States as a science experiment, seeks help from nearby Aborigines. Together they confuse Debbie into thinking it was just a bad dream.

When the Commvee is surrounded by angry seals, Eliza tries her own methods to get them to move. But she learns from her Inuit friend Jim that traditional ways have their value.

When Kip and Biederman cause an oil spill, Eliza must save her sea otter friends.

Eliza goes to desperate measures to help animals survive during tough times along the Skeleton Coast. Her good-will intentions, however, will soon cost her family their entire supply of holiday cheer--and their Christmas dinner!

When Donnie kidnaps an aye-aye for a pet, Eliza must return the ""bad luck"" omen to his home before the villagers hunt him down.

When the Thornberrys visit the !Kung people, everyone is shocked to discover that Debbie can click-talk. No one is more surprised than Eliza, however, who is only ""cured"" of her jealousy by a !Kung healing ceremony.

When Eliza ""accidentally"" reads Debbie's diary she learns that Debbie thinks she's an embarrassment of a sister. Debbie and Eliza have it out and learn the real truth about their relationship.

When a seemingly abandoned panda bear imprints on Debbie, Eliza doubts Debbie's ""parenting"" ability--until a monsoon convinces Eliza that Debbie can handle more than she lets on.

Eliza reunites with a Siberian Tiger, and is stunned when the tiger turns on her. Eliza's visiting Grandma Sophie helps her overcome her fears just as she is overcoming her own.

When the Thornberrys visit Nigel's friend Jomo, they search for an elephant named Rebecca that Nigel saved 20 years earlier. As the family attends to an elephant stuck in a mudhole, Eliza bonds with Rebecca, only to learn that she is old and ready to die.

When Eliza tries to swim with the humpback whales, Darwin accidentally knocks Debbie's boombox into the ocean, which creates a distrubing noise and causes the whales to stop their ritual singing. Eliza attempts to set things right, but ends up getting arrested for violating the Marine Mammel Protection Act.

Eliza tells Darwin the tale of how she became able to speak to animals, and how she retained her ability to speak to humans as well.

Challenging an ancient Maasai legend, Eliza marches into a ""haunted"" forest to prove her bravery. Now, with night falling, Eliza must place her trust in the mysterious legends of the Maasai in order to find her way safely through the dark forest.

When Eliza meets a group of temple monkeys, they con her into bringing all of her family's food. While Darwin tries to convince her otherwise, Eliza realizes that she's been duped and learns the value of Darwin's friendship.

The Thornberrys are invited on a cattle drive by Marianne's old high school friend whose son, Miguel, is not as adept at riding and roping as he claimed. In the end, Eliza helps him build confidence.

The Thornberrys are visited by the Foundation's head son, Tom, who splits up the Nigel and Marianne team. An over-zealous Tom treats Eliza like a child until he lands the Commvee in a raging river. Eliza's quick thinking prevails and she saves her family and wins Tom's respect.

During a drought, Eliza is forbidden to assist the thirsty animals, but she breaks her promise when she sees a cheetah cub alone on the Savannah. Eliza and Darwin are saved by a timely thunderstorm when the cheetah mother tries to eat them.

Eliza and a Chinese girl, Arioka, secretly switch places so Eliza can ride across the desert on camels and Arioka can ride in the Commvee. But Arioka's parents change their plans and Eliza must figure out a way to get them back to the Thornberrys.

Eliza is afraid to admit to her friend Ben that she doesn't know how to snowboard, just as a rutting ibex is afraid to stand up to another ibex.

Eliza and Debbie are fighting so much, Debbie decides to apply to boarding school and Eliza encourages her. But meeting up with a lone wolf teaches Eliza that families, like packs, belong together.