T-Rex Expert Sheet Expert Report: T-Rex
Partner A: Tyrannosaurus Specialist
Name:
Date:
Step 1: Read and Research (Solo)
Read the detailed report below. On the back of this page, fill in the T-Rex column of your Investigation Log.
The Tyrant King of the North
The Tyrannosaurus rex, whose name literally means "Tyrant Lizard King," remains the most legendary predator of the ancient world. This massive creature lived approximately 66 to 68 million years ago during the Late Cretaceous period. Its kingdom was located in what is now Western North America, an area scientists often call Laramidia.
Physically, the T-Rex was a masterpiece of evolution. A full-grown adult could reach lengths of 40 feet and stand nearly 12 feet tall at the hips. Despite its size, it was surprisingly agile, weighing between 8 and 9 tons. Its most terrifying feature was its massive skull, which could grow to five feet long. Inside that skull were eyes positioned at the front of its face, giving it binocular vision. This meant it could judge distances perfectly, similar to modern hawks or humans, making it a deadly accurate hunter.
The jaws of a T-Rex were capable of delivering a bite force of 12,000 pounds—enough to crush a car or, more importantly, the thick bones of its prey. Its teeth were not sharp like knives; instead, they were thick and rounded, often described as "lethal bananas." These teeth were designed for bone-crushing power rather than just slicing meat.
Interestingly, while its back legs were enormous and powerful, the T-Rex is famous for its tiny arms. Each arm ended in just two fingers. While small, these arms were actually quite muscular, though their exact purpose is still debated by paleontologists.
As a strict carnivore, the T-Rex was a solo hunter. It had an extraordinary sense of smell thanks to massive olfactory bulbs in its brain. Scientists believe it could track prey from miles away. Whether it was a pure hunter or a clever scavenger that used its size to steal meals from others, the T-Rex was undeniably the top predator of the North.
Flip to the back to log your findings!
Dino Investigation Log
Category T-Rex Findings Giganoto Findings 1. Home Continent 2. Time Period (Millions of years) 3. Length & Weight 4. Number of fingers 5. Tooth Shape & Purpose 6. Skull/Head Details 7. Senses (Vision/Smell) 8. Hunting Style (Solo/Group) 9. Diet Type
Team Test Practice
1. Based on both experts' information, select TWO shared traits.
They both lived in North America.
They were both carnivores.
They both walked on two legs.
2. How do the dinosaurs' hands contrast?
The T-Rex had more fingers.
The Giganoto had 3 fingers, but T-Rex had 2.
3. Using details from both experts, explain why these dinosaurs needed different kinds of teeth.
Comparing Giants Slides Comparing Giants
The Expert Jigsaw Mission
Standard 3.RI.9 Focus
Our Learning Mission
Standard 3.RI.9
"Compare and contrast the most important points and key details presented in two texts on the same topic."
Today, you will:
Become an "Expert" on one giant hunter.
Teach your partner about your dinosaur.
Compare them together on your Log.
Expert Teams
One reads T-Rex, one reads Giganotosaurus!
Mission Phases
1
Solo Expert
Read your specific text. Fill in ONLY your dinosaur's column on the back.
10 Minutes
2
The Exchange
Teach your partner! Tell them what you found so they can fill in their second column.
10 Minutes
3
Test Check
Work together to answer the practice questions. Use BOTH columns to find answers.
15 Minutes
Expert Protocol
A
Don't just copy! Explain your facts to your partner.
B
If your partner is confused, show them where it says it in the text.
C
Whisper voices only so other teams can focus.
Timer: 35 Minutes
"Good luck, Text Detectives!"
Giganoto Expert Sheet Expert Report: Giganoto
Partner B: Giganotosaurus Specialist
Name:
Date:
Step 1: Read and Research (Solo)
Read the detailed report below. On the back of this page, fill in the Giganoto column of your Investigation Log.
The Giant of the South
The Giganotosaurus, whose name means "Giant Southern Lizard," was one of the largest meat-eating dinosaurs to ever roam the planet. It lived roughly 97 to 100 million years ago, making it much older than the T-Rex. Its fossils were discovered in the Patagonia region of Argentina, South America.
In terms of size, the Giganotosaurus was a true heavyweight. It could reach lengths of up to 43 feet, which is actually slightly longer than the T-Rex. It weighed between 8 and 9 tons, making it similar in bulk to its northern cousin. Its skull was incredibly long, measuring over six feet, but its brain was surprisingly small—about the size of a banana. Unlike the T-Rex, its eyes were positioned more on the sides of its head, suggesting it did not have binocular vision. Instead, it likely relied on a wider panoramic view to spot movement across the landscape.
The hunting equipment of the Giganotosaurus was specialized for different prey. Its teeth were thin, flat, and jagged, almost like steak knives. These were not meant for crushing bone, but for slicing through meat and causing large wounds. This was necessary because the Giganotosaurus lived alongside massive plant-eaters, like the long-necked Argentinosaurus, which were too big for a single hunter to kill easily.
Unlike many other large theropods, evidence suggests the Giganotosaurus may have been a group hunter. Scientists have found fossils of similar dinosaurs grouped together, leading them to believe they worked in teams to take down giant sauropods. Each of its arms was larger than a T-Rex's and featured three fingers with sharp, curved claws.
As a top carnivore in a warm, lush environment, the Giganotosaurus was the ultimate predator of the South. While it might not have had the bone-crushing power of the T-Rex, its size, speed, and teamwork made it a terrifying master of its own era.
Flip to the back to log your findings!
Dino Investigation Log
Category T-Rex Findings Giganoto Findings 1. Home Continent 2. Time Period (Millions of years) 3. Length & Weight 4. Number of fingers 5. Tooth Shape & Purpose 6. Skull/Head Details
Fossil Files Answer Key Answer Key
Fossil Files: Comparing Giants (Expanded)
TEACHER RESOURCE
Standard Alignment: 3.RI.9
This expanded version requires students to synthesize information from two ~350 word texts. The 9-category log ensures comprehensive coverage of key details and physical traits.
Investigation Log Key
Category T-Rex (Expert A) Giganotosaurus (Expert B) 1. Home Continent Western North America (Laramidia) South America (Argentina) 2. Time Period 66 - 68 million years ago 97 - 100 million years ago 3. Length & Weight 40 feet / 8 - 9 tons 43 feet / 8 - 9 tons 4. Number of fingers 2 fingers 3 fingers 5. Tooth Shape/Purpose Thick/rounded ("lethal bananas"); crushing bone Thin/flat/jagged (steak knives); slicing meat 6. Skull/Head Details 5-foot skull; eyes in front 6-foot skull; eyes on sides; small brain 7. Senses Binocular vision; great sense of smell Panoramic vision; relies on movement 8. Hunting Style Solo hunter or scavenger Group hunter (teamwork) 9. Diet Type Carnivore (Meat-eater) Carnivore (Meat-eater)
Question Key
1. Shared Traits:
They were both carnivores.
They both walked on two legs.
2. Contrast Hands:
The Giganoto had 3 fingers, but T-Rex had 2.
3. Teeth Difference (Exemplary):
"The T-Rex needed thick, rounded 'banana' teeth to crush the heavy bones of its prey with its huge bite force. In contrast, the Giganotosaurus had thin, jagged teeth like steak knives because it needed to slice through meat to hunt massive sauropods in teams."
