A semi-translucent hydra, complete with a body column, head, and multiple tentacles, is pictured in front of a gray background.
How Hydras Regenerate Decapitated Heads
Hydra vulgaris constantly replenish the cells in their heads and grow new ones to reproduce asexually. But gene expression analyses reveal that regenerating a head after an injury is a very different process.
ABOVE: © ISTOCK.COM, IVAN MATTIOLI
How Hydras Regenerate Decapitated Heads
How Hydras Regenerate Decapitated Heads

Hydra vulgaris constantly replenish the cells in their heads and grow new ones to reproduce asexually. But gene expression analyses reveal that regenerating a head after an injury is a very different process.

Hydra vulgaris constantly replenish the cells in their heads and grow new ones to reproduce asexually. But gene expression analyses reveal that regenerating a head after an injury is a very different process.

ABOVE: © ISTOCK.COM, IVAN MATTIOLI

asexual reproduction

Magnified image featuring a full view of a bdelloid rotifer recovered from permafrost (labeled A) along with two insets: one side view of the organism’s head (labeled B) and a view of its mouthparts (labeled C)
Rotifers Bounce Back After Being Frozen for 24,000 Years
Lisa Winter | Jun 8, 2021
The hardy animals were pulled from the permafrost in Siberia, giving scientists the opportunity to study how they survive extreme conditions.
Image of the Day: Unusual Fungi Reproduction
Emily Makowski | Oct 30, 2019
A variety of yeasts collected near Woods Hole, Massachusetts, show unconventional cell division.
Image of the Day: Sperm Donors
Carolyn Wilke | Mar 18, 2019
Asexual female nematodes use their male offsprings’ sperm to fertilize eggs, but cast away their genes.
Horizontal Gene Transfer in Bdelloid Rotifers Questioned
Abby Olena | Jul 12, 2018
A re-analysis of sequencing data from a 2016 study of these tiny metazoans reveals possible contamination, rather than an exchange of DNA among species.
Pinpointing the Origin of Marbled Crayfish Clones
Diana Kwon | May 1, 2018
Research suggests that the invasive, all-female Procambarus virginalis originated in a German aquarium back in the 1990s.
Amazonian Fish Genome Challenges Long-Held Assumptions About Asexual Reproduction
Jim Daley | Feb 14, 2018
Poecilia formosa, an all-female fish species, has a surprisingly robust genome. 
Male Fish Borrows Egg to Clone Itself
Ruth Williams | May 23, 2017
A fish created by spontaneous androgenesis is the first known vertebrate to arise naturally by this asexual reproductive phenomenon. 
Report: Swellshark Capable of Asexual Reproduction
Joshua A. Krisch | Nov 27, 2016
Scientists use 12 microsatellites to watch as one captive female swellshark produces five pups without fertilization from a male.
Ancient Reproduction
Kerry Grens | Aug 5, 2015
Deep-sea rangeomorphs that lived more than 540 million years ago used two methods of reproduction, according to a study of fossils.
Endangered Fish Can Reproduce Without Mating
Amanda B. Keener | Jun 1, 2015
DNA fingerprinting analysis of a population of sawfish reveals evidence of asexual reproduction in the wild.
The Sex Paradox
Megan Scudellari | Jul 1, 2014
Birds do it. Bees do it. We do it. But not without a physical, biochemical, and genetic price. How did the costly practice of sex become so commonplace?
Genome Digest
Kate Yandell | Aug 1, 2013
What researchers are learning as they sequence, map, and decode species’ genomes
Wild and Sexless
Beth Marie Mole | Sep 17, 2012
Scientists find snakes give “virgin birth” in the wild for the first time
Hacking the Genome
Karen Hopkin | Jun 1, 2012
In pondering genome structure and function, evolutionary geneticist Laurence Hurst has arrived at some unanticipated conclusions about how natural selection has molded our DNA.
Self-cloning Coral
Hannah Waters | Mar 1, 2012
Coral embryos broken apart by waves can continue developing into adult clones.
Coral Clones
Hannah Waters | Mar 1, 2012
The colorful and fragile start to the life of a living reef