1. Evolutionary Shift:
Slugs, believe it or not, descended from snails. Despite lacking a shell, they've adapted well to their shell-less lifestyle. Scientists speculate that factors like calcium deficiency or high humidity levels may have contributed to the loss of their shells. Some slugs still carry a small, leathery mantle, a vestige of their snail ancestors.

2. Underground Majority:
Contrary to what you might think, the majority of slugs – about 90-95% of them – prefer the subterranean life. While you might spot a few above ground, especially after rains, the vast majority of them are busy beneath the soil, munching away and laying eggs. In fact, it's estimated that an average garden can host up to a staggering 20,000 slugs!

3. Gender Fluidity:
Slugs are true hermaphrodites, meaning they possess both male and female reproductive organs. This unique feature allows them to reproduce independently if they can't find a suitable mate. When slugs do mate, both individuals can become pregnant, leading to a prolific production of eggs.

4. Egg Machines:
The reproductive capabilities of slugs are truly impressive. A single slug can lay up to 100 eggs multiple times throughout the year. Given that both partners become pregnant after mating, the potential for egg-laying is enormous. These eggs, small and pearly white, are typically deposited in the soil, where they can remain dormant for years until conditions are just right for hatching.

5. Teeth Galore:
Surprisingly, slugs possess a vast array of teeth – depending on the species up to 27,000 of them! These teeth are arranged on a ribbon-like structure called a radula, which they use to rasp off and consume their food. Similar to sharks, slugs continuously lose and replace their teeth, ensuring they're always ready for their next meal.

6. Stretchy Wonders:
Slugs are incredibly elastic creatures, capable of stretching up to 20 times their own length. This remarkable flexibility comes in handy when navigating tight spaces or squeezing through minuscule openings in search of food or shelter.

7. Blue Bloods:
Unlike humans, who have red blood due to iron-based haemoglobin, slugs have yellowish-green blood, thanks to a molecule called Hemocyanin. This molecule aids in oxygen transport within the slug's body and gives their blood its distinctive colour.

8. Tentacle Talk:
Ever noticed the four tentacles on a slug's head? These tentacles serve different functions and are retractable. The larger pair is used for sight and smell, helping slugs navigate their environment, while the smaller pair is employed for touch and taste. Interestingly, if a slug loses one of these tentacles, it can simply regrow it.

9. Unique Signatures:
Each slug's slime trail is as unique as a fingerprint. This slime serves multiple purposes, from aiding in locomotion to marking territory and even helping slugs find their way back home. Slug slime is highly absorbent, making slugs more active in wet conditions, and notoriously difficult to wash off.

10. Slug Solutions:
While slug pellets used to be a common method for controlling slug populations, those days are long gone. Instead there are plenty of eco-friendly alternatives. Copper tape around plant pots, rough terrain with gravel or broken eggshells, and natural repellents like vinegar can all help deter slugs without harming them or the environment.


Sources:

John Innes Slug Guide
RHS Slug Guide
PlantGrow Understanding Britain's Slugs
Countryfile. How to Identify Slugs