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Interspecific comparisons identified differences in THg concentrations among snake species , with more aquatic species ( watersnakes and queen snakes ) accumulating higher mean concentrations ( 5 . 60 +/- 0 . 40 and 4 . 59 +/- 0 . 38 mg / kg in tail tissue , respectively ) than the more terrestrial species , garter snakes and rat snakes ( 1 . 28 +/- 0 . 32 and 0 . 26 +/- 0 . 09 mg / kg , respectively ) .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None