Time is a great teacher and this is especially true when we look back at some of the food and drink our predecessors consumed. Prepare to be surprised and amazed at some of the extraordinary things people have eaten over the centuries and find out why we don’t see them on menus anymore.

Christmas card cute, robins are loved for their petite size and red breasts but in previous centuries they were viewed as a tasty meal. In 1868 the Pittsburgh Weekly Gazette reported that the “people of Pensacola are shooting and eating them” whilst Wehman’s Cook Book from the late 19th century included a recipe for a pie that included ten or twelve robins. Why we don’t eat them now: robins are protected in many countries, including the US and UK.

America has the turducken, turkey stuffed into duck stuffed into chicken, but Middle Ages England went one step beyond with the cockentrice, a creation made up of a suckling pig’s upper body sewn onto the bottom half of a turkey or capon – or vice versa. These chimeras were presented as fascinating centerpieces. Why we don’t eat it now: because it’s downright weird.

According to the self-published book Living with Radiation by Paul Frame & William Kolb, back in the 1900s people with ailments including rheumatism and chronic pain drank radon water from hot springs believing it was healthy. Thankfully, bottled radon had a short half-life so its effects were minimal though one famous victim, the industrialist Eben Byers, died in 1932 after drinking the brand Radithor for two years. Why we don’t drink it now: history taught us that radiation kills.

In previous centuries, no part of an animal was wasted. An old English recipe called calf’s foot jelly is an example of this resourcefulness. It was made by boiling a calf’s foot to extract the gelatin then combining it with lemon juice, spices, sugar and wine, and sometimes egg whites, and allowing it to set. This was eaten as a dessert or pick-me-up. Why we don’t eat it now: we still eat gelatin – it’s a component in many foods from cereal to cream cheese to candy.

Turtle meat was a delicacy in 18th- and 19th-century England when its flavor was highly prized. A preserve of the wealthy, the soup was served at special occasions and banquets, often in the turtles' original shells. Why we don’t eat it now: nearly all species of sea turtle are protected though it’s eaten in China and snapper turtle soup can still be found in the US.

Anyone who’s read Alice’s Adventures in Wonderland will know that one of the characters was a mock turtle, a strange hybrid that represented this soup’s contents. Mock turtle soup is made from boiled calves’ head and sometimes brains and was a cheaper substitute for the real thing. Why we don’t eat it now: Campbell’s made a tinned version but it was discontinued. These days it’s too time-consuming to make.

Terrapins, also a type of turtle, were a regular source of food in some American states in the 18th- and 19th-century. A favorite of Franklin Roosevelt, recipes can be found in cookbooks of that time. Why we don’t eat it now: it was laborious to prepare, people don’t really eat reptiles these days or wouldn’t know how to cook them, and terrapins are often bought as pets.

Some people will go to extraordinary lengths to lose weight. In the early 1900s adverts promoted pills that included beef tapeworm cysts – the worms were meant to grow inside the intestines and absorb food. But tapeworms can cause a plethora of health problems, including headaches and epilepsy, and there’s no concrete evidence the pills were genuine. It didn’t stop desperate dieters from consuming them though. Why we don’t eat them now: it’s not only gross it’s dangerous.

Over the centuries it wasn’t unheard of for sailors to succumb to eating rats for two reasons – long sea voyages meant they were often starving and rats could eat precious supplies. Why we don’t eat them now: certain countries still eat rats but sewer rats carry disease and are to be avoided, even when cooked.

To our ancestors cow udders were just like any other edible part of the animal and were (usually) eaten without question. The famous English diarist Samuels Pepys wrote that he “had a good udder to dinner” – what he ate was probably roasted but udder was also added to pies. Why we don’t eat them now: there are a few udder recipes on the internet, and Jamie Oliver sampled one in Morocco, but this part of the cow is largely ignored.

The French added it to hot chocolate and the Persians to lemon sherbet, Casanova regarded it as an aphrodisiac, while old recipes recommended it melted like butter onto roasted game. Today ambergris is best known for giving perfume its unique musky scent but it was, and always will be, a substance excreted from whales’ rear ends. Why we don’t eat it now: there’s the odd attempt to resurrect it but the very idea turns most people off.

The nursery rhyme Sing A Song of Sixpence mentions “Four and twenty blackbirds baked in a pie”. It’s likely that this old ditty is referring to a medieval and 16th-century practice of making large pies containing live songbirds – when the pie was cut the birds flew out, creating a spectacle at feasts. Why we don’t eat them now: even though the birds weren’t cooked (they were added via a trapdoor) animal welfare would have a thing or two to say about encasing live birds in pastry.

Pemmican was the Native American equivalent of an energy bar, made from bison meat pounded into a paste then mixed with rat or deer, berries, melted fat and marrow, then dried as small cakes. Because of its high-calorie and nutritious content, it was eaten on hunting trips, during cold winters and, later on, was adopted by polar explorers. Why we don’t eat it now: the key ingredient – American bison – is now protected but there are modern versions made with buffalo.

The Mayans ate meat but had a largely vegetarian diet of squash, beans and maize. However, they did farm land-dwelling black iguanas specifically for their eggs, which are protein-rich and largely yolk. Why we don’t eat them now: iguanas are protected in many countries but it’s also that culture and economics dictate that people today eat bird eggs.

It’s hard to believe dormice were eaten, given their off-the-scale adorability, but they were a delicacy in ancient Rome where they were fattened up in a jar called a glirarium before being killed and stuffed with nuts, pork mince and their own meat, then roasted. Why we don’t eat them now: they’re protected in many countries but are still eaten in places such as Croatia.

Known in Colonial times as the ’chicken of the trees’, squirrel has been seen as an acceptable meat to eat for millennia (it tastes like a cross between chicken and rabbit). American settlers ate Colonial squirrel pie and the English dish browet farsure contained the now-endangered red squirrel and was the preserve of lords. Why we don’t eat them now: some people do, and eating plentiful grey squirrels is an ethical meat source, but consuming this rodent hasn’t caught on in the modern world.

Swans have been the property of the English crown for centuries and eating one is regarded as a crime worthy of treason. Roast swans were served at the feasts of Henry VIII and Elizabeth I but for British royalty today these beautiful birds are off the menu. Eating swans in the US isn’t illegal, however – chef Mario Batali says the meat is “lightly gamey, moist and succulent”. Why we don’t eat them now: in Britain it’s against the law; they can be eaten in the US but generally aren't.

Before coffee and tea became ubiquitous there was saloop, a popular 18th- and 19th-century English drink from the then Ottoman Empire (where it's still drunk). It consists of milk, sugar, cinnamon, rice starch and salep flour, which is made from the unappetizing orchid root. Later, this ingredient was substituted for the roots and leaves of the American sassafras tree. Why we don’t drink it now: it reportedly stopped being drunk in public when it became associated with curing venereal disease.

Mercury has proved useful to humans for centuries – it can help extract gold, was added to paint, and used in felt making and in explosive detonators. Today it can be found in thermometers and barometers. But it was also drunk to treat syphilis, and seen as an aphrodisiac and contraceptive. Why we don’t eat it now: mercury is toxic and consumption is fatal. Even repeatedly eating seafood contaminated with mercury is dangerous.

Many moons ago, in the 14th century, an English cookbook called The Forme of Cury had a recipe for roasted heron wrapped in bacon and ginger, proving this striking bird was once eaten, though probably only by the rich and royalty. Why we don’t eat them now: they were never a particularly popular bird to consume and today they’re protected, although as they will eat pretty much anything – from chickens to the koi in your carp pond – a few disgruntled people would like to see less of them.

Before the Coca-Cola of today there was the Coca Cola of yesterday – this was an uplifting and energizing drink sold between 1885-1929 that actually contained cocaine. Why we don’t drink it now: it’s long been banned from drinks but cocaine is still a ubiquitous Class A drug that can cause addiction and has a deleterious effect on the heart and brain.

Although the setting of eggs, meat and fish is associated with French cuisine, aspic is a clear savory jelly of Medieval origin. It's made from the gelatin leached from calves’ feet or veal knuckles and became hugely popular in the 18th- 19th- and early 20th-century when its firmness allowed for increasingly elaborate creations to be used as centerpieces. Why we don’t eat it now: it had a renaissance in the 1950-70s when congealed salads were all the rage but is unfashionable today.