Passage: Tuatara can live in remarkably dense populations. Most tuatara islands have 50- 100 tuatara per square hectare - so an island of only 10 hectares may have a population of hundreds. Larger islands with many seabirds and invertebrates, which tuatara eat, may have greater densities. The largest population is on Stephens Island, where there are estimated to be as many as 2,500 per hectare in some places, and a total of at least 30,000. The total number of tuatara on all the islands is estimated to be between 50,000 and 100,000.

Question: Density of tuatara on Stephens Island is up to _______ tuatara for every hectare.

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