Symbolism of lion with forked tail

The lion rampant with forked tail is a traditional emblem of Bohemia, now the Czech Republic, first evidenced on the seal of King Vladislaus II of Bohemia granted by Emperor Frederick Barbarossa in the mid to late 13th century.

The forked nature of the tail is not meant to represent a mythical or unusual creature; rather it is to represent a moving tail, or a wagging tail if you will.

A desirable coat of arms is one that is very simple and easy to remember. It is also desirable to have a coat of arms that is unique, different from everyone else's. But that was always hard to achieve.

A coat of arms with a lion rampant of a single color on a field of a single color was very popular in early heraldry. But since there are only 2 metals and 5 main colors in heraldry and a rule against putting a metal charge on a metal field or a color charge on a color field, there were only about 20 simple combinations available.

Possiblities are: A field of silver, with a lion either red, green, blue, purple, or black. A field of gold, with a lion either red, green, blue, purple, or black.

A field of red, with a lion either silver or gold. a field of green, with a lion either silver or gold. A field of blue, with a lion either silver or gold. A field of purple, with a lion either silver or gold. And a field of Black, with a lion either silver or gold.

So those possibilities soon ran out.

Even kings often did not adopt coats of arms quick enough to snatch up an unused simple combination of a lion rampant of a single color or metal on a field of a single color or metal and had to settle for more complex designs.

Royal coat of arms of Norway.

https://www.google.com/search?q=lions+in+heraldry&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiCmtmZ9LbUAhWCHT4KHeuWA44Q_AUICigB&biw=1280&bih=894#tbm=isch&q=coats+of+arms+of+Norway1

Royal coat of arms of Sweden. Note that the quartering of the Folklunga or Bjelbo dynasty with a lion rampant has it on a 2 colored field.

https://www.google.com/search?q=royal+coat+of+arms+of+scotland&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwjm3PKJ-LbUAhXLFz4KHTcmBqQQ_AUIBigB&biw=1280&bih=894#tbm=isch&q=royal+coat+of+arms+of+seden2

https://en.wikipedia.org/wiki/House_of_Bjelbo3

The coat of arms of Denmark doesn't even have a lion rampant.

https://en.wikipedia.org/wiki/Coat_of_arms_of_Denmark#/media/File:Coat_of_arms_of_Valdemar_IV_of_Denmark.svg4

https://en.wikipedia.org/wiki/Coat_of_arms_of_Denmark#/media/File:National_Coat_of_arms_of_Denmark.svg5

The lion rampant in the Scottish coat of arms soon acquired a double tressure flory counter flory.

https://www.google.com/search?q=royal+coat+of+arms+of+scotland&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwjm3PKJ-LbUAhXLFz4KHTcmBqQQ_AUIBigB&biw=1280&bih=894#imgrc=_6

The Royal coat of arms of England, which does not have one lion rampant.

https://en.wikipedia.org/wiki/Royal_Arms_of_England#/media/File:Royal_Arms_of_England_(1198-1340).svg7

The royal or princely coat of arms of Gwynedd or Wales.

https://en.wikipedia.org/wiki/Welsh_heraldry#/media/File:Coat_of_arms_of_Wales.svg8

The royal coat of arms of Leon:

https://www.google.com/search?q=royal+coat+of+arms+of+Leon&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiPyoXZgbfUAhXLCD4KHXL4A6IQ_AUICigB&biw=1280&bih=8949

The Royal coat of arms of Cyprus:

http://www.wikiwand.com/en/Kingdom_of_Cyprus10

It is the third quarter in the coat of arms of Cyprus, barry of eight argent and azure (silver and blue) with a lion rampant gules (red):

The royal coat of arms of Lesser Armenia:

http://www.wikiwand.com/en/Kingdom_of_Cyprus10

It is the third quarter in the royal coat of arms of Cyprus, a gold field with a red lion rampant.

And the royal coat of arms of Dalmatia:

http://www.wikiwand.com/en/Kingdom_of_Cyprus10

Has three lion faces.

And the royal coat of arms of Bohemia:

https://www.google.com/search?q=royal+coat+of+arms+of+bohemia&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjQiJ2XirfUAhXEDj4KHaqgB0YQ_AUICigB&biw=1280&bih=89411

Other medieval European kingdoms did not use lions in the royal coat of arms, such as France, Portugal, Castile, Navarre, Aragon, Sicily, the other Sicily, Croatia, Hungary, and Poland.

Thus it is obvious why the lion rampant in the coat of arms of Bohemia has a forked tail to make it look different from other medieval lions rampant. And that goes for the lion in John de la Pole's heraldry also.

It's worth noting that the lion with a forked tail (queue forchée) is on John de la Pole's heraldry, which you can see below. That shows the heraldry from his wife's family, quartered with the De la Pole heraldry he inherited. The lion originates on the Burghersh family heraldry -- De la Pole's wife, Alice, was the daughter of Thomas Chaucer who had married a Burghersh heiress.

(Yes, those Chaucers. Alice was Geoffrey's granddaughter.)

Now, regarding the meaning of the forked tail -- John Bossewell's Workes of Armorie (1572) had this to say:

"Here the Lyon his tayle is forked. For by the taile his boldenesse, and harte is knowne, as the horse is knowen by the eares. For when the Lyon is wrothe, first he beateth the earthe with hys tayle, and afterwarde as the wrathe increaseth, he smiteth, and beateth his own backe."

(Source, and see the screen shot below.)