Height at Shoulder:
- Adult male: On average, 2–2.7 m (6.5–8.8 ft)
- Adult female: Typically around 2 m (6.5 ft)
Total body length:
- Approximately 5–6 m (16.5–19.7 ft)
Weight:
- Adult male: Reaching weights up to 8–10 metric tons (8,000- 10,000 kg)
- Adult female: Typically around 6–7 metric tons (6,000–7,000 kg)
Tusk length:
- Upper tusks (long and curved): Up to 5 m (16.5 ft) long in adult males, but females rarely developed upper tusks.
- Lower tusks (short and straight): Up to 30–45 cm (12–18 inches) long in both males and females.
It's important to note that these measurements represent average sizes and there could be some variations among individuals within the species. The American mastodon was a large mammal, but it was generally smaller than the woolly mammoths (Mammuthus primigenius), which coexisted with them during the Pleistocene epoch.