Since a turkey's wattle is red, it means that something is red.
This is not an idiom. When you see AS ___ AS ___, you are looking at A Simile. This one is comparing something to the red color of a turkey's wattle.
The phrase "as red as a turkey gobbler's wattle" in "Where the Red Fern Grows" describes a bright red color similar to the wattle, or the fleshy skin hanging from a turkey's throat. In this context, it symbolizes the vibrant and intense hue of the red ferns that stand out among the greenery in the story.
This phrase is a simile used to describe the red color of the dogs' paws. It means that their paws were a bright, vibrant shade of red, similar to the color of a turkey gobbler's wattle.
a wattle
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The red fleshy appendage you see on a turkey's neck is their wattle.
a wattle
A wattle.
The fleshy part that hangs from a turkey's neck is called a wattle.
The red ornament on a turkey's head is called a wattle.
It is called a wattle and part of the birds sexual display mechanism.
The red thing you are referring to is called a wattle. It is not clear why turkeys have them but it is likely that they are used to attract the opposite sex and/or to scare away other male turkeys. When the male turkey gets excited the red wattle enlarges in size perhaps making it look more attractive to the opposite sex and scary to the same sex. This is similar to an erect cock on a human male, as the increase in blood flow helps attract mates while scaring off other males. Not much information about turkey wattles can be found. Hope this helps. The wattle helps to cool the turkey. The bright red area has blood flow close to the surface and as it is not covered by feathers it gets cooler faster. Turkeys do not sweat.