By Maneka Sanjay Gandhi
An egg is an organic vessel in which an embryo develops. Every animal’s primal need to reproduce has resulted in an astonishing range of solutions to parental care. From delivering new-borns ready to take on the world, to parents giving up eating to hold eggs in their mouth, species have developed behaviour that ensures the survival for their offspring.
The Surinam toad’s eggs land on the female’s back. She grows skin around each one, which can be up to 100, forming a honeycomb structure. The eggs hatch and develop inside these skin pockets over the next four months. Offspring pop out as fully formed toadlets.
Another odd birthing behaviour is mouth-brooding, where offspring are incubated in their parent’s mouth. Cichlids are mouth-brooders – the female lays her eggs and then picks them up in her mouth. The male fertilises them in her mouth, and the eggs stay there. They hatch in seven days, but some parents continue to carry the fry for another few weeks, forgoing food until the young are released. Since many fish eggs die from fungus, predation and being swept away, mouth-brooder eggs ensure that the maximum survive.
Male Seahorses grow special birthing pouches on their stomachs. The female seahorse lays her eggs in the male’s pouch, and then he fertilises and incubates the eggs until he gives birth. The Leafy Seadragon has long leaf-like protrusions coming from all over the body used as camouflage. The female produces up to 250 bright pink eggs and then deposits them on to the male’s tail via a long tube. A brood patch on his skin supplies them with oxygen. Over the nine weeks that it takes for them to hatch, the eggs turn a ripe purple or orange, after which the male pumps its tail until the infants emerge. Pipefishes, like seahorses, leave the parenting duties to the male pipefish, which have a specially developed area to carry eggs, deposited by the female. In some species this is a patch of spongy skin along the pipefish’s underside that the eggs adhere to until hatching.
Betta and Gourami male fish build a bubble nest - a floating “saliva mat” of air-bubbles and plant matter. As soon as the mating is over the female releases the eggs into the water. The male gathers the eggs and spits them up into the bubble nest. After spawning, the male has no further use for the female and attacks her and other fish that approaches the nest.
Octopuses string thousands of soft, translucent eggs up on overhangs of rock or coral.
Penguins always lay two eggs in a shallow hole in the sand. They put plants and stones inside the nest. Only one survives.
Eggs across the animal kingdom can be spectacular – even those of the common chicken. Chicken from the same coop often lay differently coloured eggs. There are over 50 breeds and you can make out from their earlobes what colours the eggs will be. The Leghorn lays white eggs and has white earlobes. Chickens with red earlobes lay brown-shelled eggs - except the Lamona chickens which have red earlobes, but lay white eggs. Araucanas lay pale blue eggs and when crossed with a breed that has eggs of a different colour the resulting eggs are blue, pink, or green. Interestingly, the gene for blue egg shells is closely related to the gene for a pea comb on the hen’s head. The Marans lay a deep brown egg. Other species lay lavender, olive green and red eggs. Cochin and Plymouth Rock hens lay light brown eggs. Easter Eggers lay pink eggs and Croad Langshans lay plum collared eggs.
Magically, wild birds produce egg colours that can be camouflaged easily. Plovers that lay their eggs in sand have sand coloured eggs. (Imagine if a white person lived in Africa and could change the colour of the baby in order to blend in.)
Japanese quails produce speckled eggs and lay them in areas where the speckling will blend in and hide the eggs.
On the other hand the Tinamou (a relative of the ostrich) lays shiny, turquoise eggs in order to draw attention to them so that all the other females lay their eggs nearby and guard them collectively. The Emu lays beautiful deep green eggs the size of a hand.
Some insects produce eggs that are works of art. The Green Lacewing creates a silky stalk, which it coats with a chemical defence against other insects, on which to hang its eggs. The eggs of the Common Castor Butterfly are a shimmering white with long white filaments surrounding them. The 400 miniscule white eggs of the Preying Mantis are laid in a frothy mass which hardens into a protective shell.
The Horn Shark egg case is spiral shaped and it looks like a drill bit. The egg cases' spiral structures allow the female to screw them into crevices, making it tougher for predators to get them. The Skate’s egg cases are shaped like ravioli and have tendrils that attach them to rocks. The egg cases of sharks, skates, and rays can breathe, unlike the shells of chicken eggs. Water and oxygen go back and forth between them, and waste products are able to fuse out. Most sharks and skates egg cases are square or rectangular with stringy or pointy corner horns. Some shark eggs contain several baby sharks which cannibalize each other before hatching to ensure that only the strongest baby survives.
Lamprey eels have light green eggs that have two external frills on the side that make them look like wrapped sweets. The hagfish has peach coloured eggs that look like long medicine capsules.
The female cuttlefish lays eggs which are kept in a sturdy, pillow-shaped capsule, coloured with ink. The inky, grapelike clusters on the seafloor are left alone by the mother. During that time, the egg sacs grow thinner and clearer, losing their inky camouflage and, within a week or two of hatching, allowing the baby cuttlefish to peer out of their protective bubble, learning to recognize prey even before they hatch. By the time it hatches, a cuttlefish is completely prepared for a life of hunting shrimp and evading predators.
How amazing every species is. To think that most of them will not be here by the next century is so sad.
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