When the word ‘bean’ enters your mind I’m sure you would picture a type of food? Something in the shape of a kidney or maybe something that leads to the flavours of coffee? Well not in this case… Do you know what is behind the jump of the jumping bean?

The deserts of mainland Mexico are home to many fascinating wild plants and animals – but the most intriguing of all is the Mexican jumping bean. Produced by a native shrub or small tree, the bean becomes harvested and shipped to novelty shops and vendors often around American where it has become famous. For such a demanding sell, why are these beans so interesting? The answer to this one is their unpredictable movements and the long lasting tales which have followed them.

jumping bean

Image Source -The Pulitzer

Children’s hands are often on the fun chase for catching these jumping beans on the lands where they grow wild. Except for the few which are saved for children to giggle and watch under trees the rest are sold to local dealers which become exported to the USA to meet demands for one of the worlds most popular beans.

So what’s the big deal about?

The Mexican jumping bean, despite its name is actually not a bean at all but is a fascinating product of a deciduous shrub composed of dark leathery leaves that transforms into an impressive blaze of red during the winter months. These are often found splattered out across rocky desert slopes – but the best location known as the ‘jumping bean capital of the world’ is the district of Alamos Mexico.

Freshly cut stems of the jumping bean shrubs radiate a poisonous milky sap. One so poisonous that it has believed to be one of the many magical items of nature the native Indians used to apply poison to their arrow tips. Because of this wonder, in some areas they have become renamed as the “herbs of the arrow.”

Image Source – Fontplaydotcom

Jerking, rolling and foolishly moving about in an everlasting motion is the greatest marvel behind these well known beans. But causes this movement? The answer is often unknown when asked, but the truth behind it all is the larvae of a small gray moth. It is this vigorous yellow to white larvae that hosts such an unusual behaviour of forcefully throwing itself from one side of the wall of its capsule to the other – thereby causing the bean to jump, roll and move about. Here is a link of collected videos, were you can see these beans in action.

It is these sections of the beans that become cut out, sold and become reputable around the world as the “jumping bean”. The reason behind such a bizarre behavior is in fact a measure of survival. In order to protect themselves from heat – they jump (a gradual process of movement) to places with cooler temperatures. Remaining in the sun for extended periods of time would result in dehydration and death.

Image Source – The Pulitzer

The moth behind all this belongs to a large family of moths known as the Olethreutidae and is called the jumping bean moth. Many people hate it and constantly perceive these moths as agricultural pests – causing damage and economical loss. Both the moth during its adult and larval stage often live in fruits, feeding on the tissue inside – resulting in fruit favorites becoming attacked and unfit for selling.  Luckily for Mexicans the jumping bean moth does not cause too much of a negative impact as the value behind these beans has turned on their heads receiving a great deal of income during spring and summer months when this bean is most abundant.

This is the time for the shrubs to bloom, allowing the female moth to lay her eggs on the green immature capsules of female flowers – a small start to the large interest of the bizarre movements found within their offspring. Towards the ending of summer the capsules of the Mexican jumping bean shrub separates into three sections – each splitting open and ejecting its seed. Those hollowed out sections that contain moth larvae fall to the ground – the beginning of the hunt and find for the jumping and hopping beans of Mexico.

Image Source – Ifood

Those larvae that are left untouched can live for months inside the bean with varying periods of dormancy.  If provided with the right conditions of temperature and moisture the larva survive long enough to reach its pupa stage. By the start of spring the moth forces its way out of the bean through a trap door, completely leaving behind the pupa casing. Unfortunately, after investing so much energy into morphing into a silver-grey coloured moth, these only experience life for just a couple of days.

Image Source – andresmh

So there you have it – the truth behind the peculiar and entertaining movements of the Jumping bean. Foretold in many stories and sold widely across the USA is a remarkable form of larvae that can never be forgotten.

I would just like to thank Karl Pilkington from Sky1’s Idiot abroad TV series for intriguing and inspiring me to take a look into the world of Mexican Jumping Beans. Click here to see Karl’s quest to find them during his travels through Mexico. I would never have written about these jumping beans witout him!

  • adam

    Haha I watched karls seven wonders and saw the hunt for his mexican beans. You must have been as curious as me. Great topic!

  • Dane

    These are amazing! Where can I get them from? Do we have them in hthe Uk?

  • JP

    Awesome subject to write about, i also saw it on Karl ha ha. Again tatefully documented and well written. I like the diversity in your topics, not seen any new stuff for a while? Come back and write more im eager to discover and learn new things you write about!

  • Lynx

    You are a very diverse writer. When I saw the link to this on stumble upon I thought hmm… but I am very glad I clicked on it because this was a great story, its good to see that someone can make a bean interesting!