Sumatran rhinoceroses, like other rhino species, experience growth during their early years. On average, Sumatran rhinos can grow about 1 to 2 centimeters (0.4 to 0.8 inches) per month during their first year of life. However, it's important to note that the growth rate can vary depending on factors such as nutrition, genetics, and overall health.
During their first year, Sumatran rhinoceros calves rely heavily on their mother's milk for nutrition and growth. As they grow older, their diet slowly transitions to include more solid vegetation, such as leaves, fruits, and shoots.
Sumatran rhinos generally reach their full size and weight as adults, which is typically between 1,300 to 2,000 kilograms (2,900 to 4,400 pounds), by around 8 to 10 years of age.