THE FROG 
HE FROG is not so easily tamed as the 
toad, but it makes an attractive inhabi- 
tant of the aquarium. It is slimmer 
than the toad, and is not covered with 
warts. It is slippery to the touch, and, 
like the toad is cold, for both of them 
are cold-blooded creatures, which means 
their blood is the temperature of the surrounding 
atmosphere. The blood of a warm-blooded animal 
maintains a certain temperature whether the sur- 
rounding air is cold or hot. 
The frog is quite as good a jumper as the toad, and 
is a far more powerful swimmer, since it lives most 
of the time in or very near the water. The frog 
shows its relation to the water by being the color of 
the brook bottom, or of the water-plants, green and 
yellow being its prevailing hues. The frogs, like the 
toads, have the power of changing color more or less 
to match their surroundings. 
The common green frog, the leopard and pickerel 
frogs are those most commonly kept in the aquarium. 
These species like to stay in the water, but they find 
most of their food in the rushes, or other vegetation 
along the banks of streams or ponds. ,, These frogs 
are all attractive singers. 
The bullfrog is also a common aquarium pet, but 
he cannot be trusted in the same tank with any frogs 
or other creatures less huge than himself. He is the 
most aquatic of all our frogs, and can remain beneath 
water for a longer period than any. Nevertheless, he 
likes to come out on a flat stone and enjoy the air and 
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