Simplify the following text for a Grade 3 native English-speaking person.
Original: Older males can get much larger , reaching at least 3200 k and occasionally weighing 4500 k. Male hippos appear to continue growing throughout their lives ; females reach a maximum weight at around age 25 .
Simplified: Older males can get even bigger . They are at least 3200 k and sometimes even weigh 4500 k.