plants that are unappealing to animals?

Question

What would be an example of a plant that uses colors to deter predators? Like for example---a plant that looks like another posionous plant so predators stay away from it.

Answer 1

well as already pointed out having some form of spine can deter animals as well as cacti you can have gorse, boxthorn, thistles, roses even.......but some animals eg giraffe can eat boxthorn regardless of the spines.

I know that leaves can build up tannins and other chemicals that is not well liked by insects/animals eg Oak leaves have tannins, there is very little in younger leaves and these are eaten with a vengence by insects etc but as the tannins increase they are less palatable to them and are not eaten as much.

Some of the deadliest poisons come from plants, in particular the akaloids..nasty chemicals.....this would obviously deter animals...I am assuming it would kill some, but some would make them pretty ill (and vomit) would be avoided in the future.....
Sometimes colour of things is important...eg green berries (unripe) are not as attractive to birds as red/orange/yellow (or ripe) ones....you know too when you have a "green" fruit too.
Having tough leaves that are very hard to chew/bite etc and offer little nutritional value would also deter some animals from eating it.

Answer 2

In late summer, when the grass has died back a bit, the bright yellow fruits of nightshade are easily distinguishable... and I stay away from them. They're around for quite awhile, too- so the colour might be detering predators.
But it is more likely the flavour.

Answer 3

cactus have spines/needldes to scare away its animal life in the vacinity stay away.
milkweed plant sticky exudate is yucky to some insects.