Gallimimus
- When: Late Cretaceous
(70 mya) - Where: Asia
- What: Theropod
- Weight: 440 kg
- Length: 6 meters
- Diet: Omnivorous
- Discovered: 1972
Giganotosaurus
- When: Late Cretaceous
(98–97 mya) - Where: South America
- What: Theropod
- Weight: 8–13 tons
- Length: 12–13 meters
- Diet: Carnivorous
- Discovered: 1995
Gigantopithecus
- When: Miocene to Pleistocene
(9 million–100,000 years ago) - Where: Asia
- What: Mammal
- Weight: 500 kg
- Length: 3 meters
- Diet: Herbivorous
- Discovered: 1935
Gigantoraptor
- When: Late Cretaceous
(85 mya) - Where: Asia
- What: Theropod
- Weight: 1.4 metric tons
- Length: 8 meters
- Diet: Omnivorous
- Discovered: 2007
Giraffatitan
- When: Late Jurassic
(154–150 mya) - Where: Africa
- What: Sauropod
- Weight: 20–40 tons
- Length: 21–24 meters
- Diet: Herbivorous
- Discovered: 1914
Glyptodon
- When: Pleistocene
(2 million–10,000 years ago) - Where: South America
- What: Mammal
- Weight: 1–2 metric tons
- Length: 3 meters
- Diet: Herbivorous
- Discovered: 1839
Hadrosaurus
- When: Late Cretaceous
(80–75 mya) - Where: North America
- What: Hadrosaur
- Weight: 2.5 metric tons
- Length: 7–10 meters
- Diet: Herbivorous
- Discovered: Joseph Leidy in 1858
Herrerasaurus
- When: Late Triassic
(231–228 mya) - Where: South America
- What: Theropod
- Weight: 210–350 kg
- Length: 4–6 meters
- Diet: Carnivorous
- Discovered: 1963
Heterodontosaurus
- When: Early Jurassic
(200–190 mya) - Where: Africa
- What: Ornithischian
- Weight: 2 kg
- Length: 1 meter
- Diet: Herbivorous
- Discovered: 1962