...The pugnacious spirit is one of the necessities of life... 
David Livingstone 「The Last Journals of David Livingstone, in Central Africa, from 1865 to His Death, Volume II (of 2), 1869-1873」
...They are one of the most pugnacious and courageousof birds attacking and driving away anyfeathered creature to which they take a dislike,regardless of size...
Chester A. Reed 「The Bird Book」
...The Chingolos pair about the end of September, and at that timetheir battles are frequent, as they are very pugnacious...
P. L. Sclater 「Argentine Ornithology, Volume I (of 2)」
...They are, however, pugnacious little things,and have only the grand forbearance of bigger dogsto thank for the prevention of many a tragedy dueto uppish self-assertion...
Mrs. Leslie Williams 「A Manual of Toy Dogs」
...But you mustn’t run away with the idea that black Tom is a pugnacious animal, or fond of fighting for fighting’s sake...
Gordon Stables 「The Domestic Cat」
...One day the bird came to the gate as usual, and was more alert and pugnacious than ever; and no wonder, for his mate came too, and with them four young birds...
W. H. Hudson 「Birds in Town and Village」
... pugnacious...
W. H. Hudson 「Birds in Town and Village」
...Crocodiles show an occasionalcannibalistic tendency, while water-shrews are very pugnacious andoftentimes fight until one is killed...
Royal Dixon 「The Human Side of Animals」
...In a few cases also thefemale is much the more masculine, noisy, and pugnacious...
John Burroughs 「Ways of Nature」
...How pugnacious the robin is! With what spunkand spirit he defends himself against his enemies!Every spring I see the robins mobbing the blue jaysthat go sneaking through the trees looking for eggs...
John Burroughs 「Ways of Nature」
...At the smalllake where they were then encamped, there was the ever-present likelihoodof a conflict with the pugnacious natives of the Darling...
Ernest Favenc 「The Explorers of Australia and their Life-work」
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