original: Some of the animals weighed as much as 700 kg (1,500 lb) or possibly larger.
simplifications: Some of the animals weighed as much as 700 kg (1,500 lb) or more. Some of the animals weighed more  than 700 kg. Some of the animals weighed 700 kg or more. Some of the animals weighed 700 kg (1,500 lb) or more. Some animals weighed as much as 700 kg (1,500 lb) or larger. Some of the animals weighed as much as 700 kg. Some may be larger. Some of the animals were as heavy as 700 kg or even larger. 700 kg is around 1,500 lbs. Some animals weighed 1500 lbs or more. Some of the animals weighed 700 kg (1,500 lb) or more. Some of the animals weighed as much as 700 kg (1,500 lb) or maybe more.