#dropsofscience

ESP version ITA version

Instagram Facebook Linktree

They may all look the same at first glance, but today we know that there are more giraffe species than previously thought. A recent review by the International Union for Conservation of Nature (IUCN), based on original and updated data as well as expert opinions, has recognised the existence of four distinct species and several subspecies. The definition of the number of giraffe species that exist has always been a matter of debate among scientists worldwide. In fact, in 2016, it was believed that there was only one species with as many as nine subspecies. So, what led to this update? Genetic and genomic analyses carried out on existing giraffe populations have been made possible by recent scientific advances.

The assessment was conducted using the so-called “traffic light system,” already applied to other animal groups such as canids and felids. This method combines multiple converging lines of evidence: morphological/phenotypic characteristics (physical traits distinguishing one population from another), genetic data (to reconstruct close and distant relationships), and biogeographical information (showing how populations have been distributed and separated in the past and present).

The traffic light categories are:

Distinct (green): three or more independent lines of evidence indicate clear differences.

Probably distinct (yellow): multiple lines of evidence suggest differences, but further research is needed.

Unknown/Invalid (grey): little or no available evidence.

Not distinct (red): no evidence of separation, or published studies confirm conspecificity or subspecificity.

A key contribution to this review came from 3D morphometric analysis of 515 giraffe skulls from across Africa. By contrast, the coat pattern — although distinctive — is not considered a reliable criterion, as its shape and colour vary with age and population.

The combined data clearly distinguished (green light) the following species, with their respective subspecies:

Giraffa camelopardalis (G. c. antiquorum, G. c. peralta, G. c. camelopardalis)

Giraffa reticulata

Giraffa tippelskirchi (G. t. tippelskirchi, G. t. thornicrofti)

Giraffa giraffa ()

These taxonomic updates are crucial for conservation, as they provide a clearer picture of giraffe diversity and offer a solid foundation for targeted management of their populations.

See You Soon and Good Science!

ESP version ITA version

Observing animal behavior is essential to understanding their biology and improving their well-being, both in the wild and in captivity. This also applies to model organisms, species used in scientific research. These animals are often studied in laboratories to investigate complex biological phenomena in controlled environments. However, natural habitats are more complex, and animal behavior may differ significantly between the lab and the wild.

For example, in laboratories, the small freshwater fish medaka (Oryzias latipes) is known to court and spawn shortly before dawn. But does this happen the same way in nature? A research team from Osaka Metropolitan University set out to find out. Despite the widespread use of this species in scientific studies, little is known about its natural ecology. To bridge this gap, researchers installed underwater cameras in a watercourse in Gifu, Japan, monitoring a wild population for ten days. The video analyses confirmed the nocturnal activity of the species, revealing surprising findings.

First, medaka fish began spawning around midnight, several hours earlier than reported in laboratory studies. From that moment on, swimming activity increased rapidly, peaking between 1 and 3 AM. Male medaka displayed two main courtship behaviors: chasing females and performing rapid circling in front of them, particularly intense between 2 and 3 AM.

But why does medaka reproduce at night? Researchers hypothesize that this behavior helps reduce the risk of predation on eggs and adults. Many fish species reproduce at night or twilight when predators are less active. Additionally, medaka does not rely solely on vision for courtship but uses chemical signals to recognize mating partners, allowing them to reproduce even in the dark.

These discoveries add new insights into the natural behavior of medaka and could improve its care in captivity by creating less stressful laboratory environments. Understanding model organisms in their natural habitat not only enhances animal welfare but also improves the reliability of scientific research.

See You Soon and Good Science!

Source

ESP version ITA version

You are walking along trails you’ve hiked dozens of times when suddenly, you start wondering about the greenish-gray crusts on trees you often pass by. Equipped with paper bags, always handy in a professional lichenologist’s backpack, you begin sampling carefully. You send the samples to a colleague for a more precise identification and—surprise, surprise—four of them turn out to be completely different from the others.

At first, you classify these samples under the genus Lepraria due to some similarities, such as the very fine thallus that crumbles into granules. However, something feels off. You soon realize that these four specimens are not as green as you initially thought. Their crust has a bluish tint, with shades between turquoise and dark aqua-green—something neither of you had ever seen in any other lichen before. Not only that, but molecular analyses on the extracted DNA sequences place the specimens in another genus, Leprocaulon to be precise, without matching any previously sequenced species.

The plot thickens, and your research group expands. You decide to involve other experts to sequence the DNA from a larger sample size beyond the initial four specimens. More samples are collected, and now you are anxiously awaiting the results, as if you were waiting for the outcome of a paternity test.

And finally, what you had hoped for—but were hesitant to say out loud—becomes reality: you have just discovered a new species of lichen for Italy! But there’s more: the symbiotic alga—since lichens are living beings mainly composed of a symbiosis between a cyanobacterium (or an alga) and a fungus—also turns out to be new to science and belongs to the genus Symbiochloris!

Now comes the challenge of choosing a name. Since the first specimens were collected in the Ticino Valley, the research team initially leaned toward Leprocaulon ticinense. However, you—the lichenologist who first collected them—decide to take another walk, this time in Val Camonica. And what do you find on a chestnut tree? That same bluish lichen, in a completely different habitat. The initial name is thus discarded, and given the constant surprises this tiny living organism has provided and continues to provide, there is only one possible choice: Leprocaulon inexpectatum.

This discovery proves that, despite environmental degradation, there are still islands of biodiversity that persist and hold surprises. And who knows? Maybe the next new species is just waiting to be found by you, on one of your usual trails!

See You Soon, and Good Science!

ENG version ESP version

Instagram Facebook Linktree

Potranno sembrare tutte uguali a prima vista, ma oggi sappiamo che esistono più specie di giraffe di quanto si pensasse. Una recente revisione dell’Unione Internazionale per la Conservazione della Natura (IUCN), basata su dati originali e aggiornati e sul parere di esperti, ha riconosciuto l’esistenza di quattro specie distinte e di diverse sottospecie. La definizione di quante specie di giraffe esistano è sempre stata oggetto di dibattito e confronto tra gli scienziati di tutto il mondo, tanto che nel 2016 si era arrivati a pensare che ce ne fosse solo una e ben nove sottospecie. Quindi cosa ha portato a questo aggiornamento? Le analisi genetiche e genomiche compiute sulle popolazioni di giraffe esistenti, rese possibili dai progressi scientifici degli ultimi anni.

La valutazione è stata condotta con il cosiddetto sistema “a semaforo”, già applicato ad altri gruppi animali come canidi e felidi. Questo metodo combina più linee di evidenza, ovvero di prove, convergenti: caratteristiche morfologiche/fenotipiche (tratti fisici che distinguono una popolazione da un’altra), dati genetici (per ricostruire le parentele vicine e lontane) e informazioni biogeografiche (che mostrano come le popolazioni si sono distribuite e come si sono separate nel passato e nel presente).

Le categorie del semaforo sono:

Distinto (verde): 3 o più linee di evidenza indipendenti indicano differenze nette.

Probabilmente distinto (giallo): più linee di evidenza suggeriscono differenze, ma servono ulteriori ricerche.

Sconosciuto/Non valido (grigio): poche o nessuna prova disponibile.

Non distinto (rosso): non esistono evidenze di separazione, oppure studi pubblicati dimostrano conspecificità o sottospecificità.

Un contributo chiave alla revisione è arrivato dall’analisi morfometrica 3D di 515 crani di giraffa provenienti da tutta l’Africa. Al contrario, il mantello — per quanto caratteristico — non è considerato un criterio affidabile, non raggiunge il cosiddetto “gold standard” poiché disegno e colore variano con età e popolazione.

Dall’insieme dei dati sono risultate chiaramente distinguibili (semaforo verde) le seguenti specie, con le rispettive sottospecie:

Giraffa camelopardalis (G. c. antiquorum, G. c. peralta, G. c. camelopardalis)

Giraffa reticulata

Giraffa tippelskirchi (G. t. tippelskirchi, G. t. thornicrofti)

Giraffa giraffa (G. g. giraffa, G. g. angolensis)

Questi aggiornamenti tassonomici sono fondamentali per la conservazione, perché offrono un quadro più chiaro della diversità delle giraffe e forniscono basi solide per una gestione mirata delle loro popolazioni.

ENG version ITA version

Instagram Facebook Linktree

A primera vista pueden parecer todas iguales, pero hoy sabemos que existen más especies de jirafas de lo que se pensaba. Una reciente revisión de la Unión Internacional para la Conservación de la Naturaleza (UICN), basada en datos originales y actualizados y en la opinión de expertos, ha reconocido la existencia de cuatro especies distintas y varias subespecies. La definición de cuántas especies de jirafas existen siempre ha sido objeto de debate entre los científicos de todo el mundo. De hecho, en 2016 se pensaba que solo existía una especie con hasta nueve subespecies. Entonces, ¿qué llevó a esta actualización? Los análisis genéticos y genómicos realizados sobre las poblaciones existentes de jirafas, posibles gracias a los avances científicos de los últimos años.

La evaluación se llevó a cabo con el llamado “sistema de semáforo”, ya aplicado a otros grupos animales como los cánidos y los félidos. Este método combina varias líneas de evidencia convergentes: características morfológicas/fenotípicas (rasgos físicos que distinguen una población de otra), datos genéticos (para reconstruir relaciones cercanas y lejanas) e información biogeográfica (que muestra cómo las poblaciones se distribuyeron y se separaron en el pasado y en el presente).

Las categorías del semáforo son:

Distinto (verde): tres o más líneas de evidencia independientes indican diferencias claras.

Probablemente distinto (amarillo): varias líneas de evidencia sugieren diferencias, pero se necesitan más investigaciones.

Desconocido/No válido (gris): pocas o ninguna prueba disponible.

No distinto (rojo): no existen evidencias de separación o estudios publicados confirman conespecificidad o subespecificidad.

Una contribución clave a esta revisión provino del análisis morfométrico 3D de 515 cráneos de jirafas de toda África. En cambio, el pelaje —por muy característico que sea— no se considera un criterio fiable, ya que su diseño y color varían según la edad y la población.

Del conjunto de datos resultaron claramente distinguibles (luz verde) las siguientes especies, con sus respectivas subespecies:

Giraffa camelopardalis (G. c. antiquorum, G. c. peralta, G. c. camelopardalis)

Giraffa reticulata

Giraffa tippelskirchi (G. t. tippelskirchi, G. t. thornicrofti)

Giraffa giraffa (G. g. giraffa, G. g. angolensis)

Estas actualizaciones taxonómicas son fundamentales para la conservación, porque ofrecen una visión más clara de la diversidad de las jirafas y proporcionan bases sólidas para una gestión específica de sus poblaciones.

¡Hasta Pronto y Buena Ciencia!

ENG version ITA version

Instagram Facebook Linktree

La ciencia ha confirmado repetidamente que la temperatura media de océanos, mares y lagos está aumentando como consecuencia del cambio climático de origen humano. Lo que resulta menos claro es cómo están cambiando los extremos de temperatura, tanto bajos como altos. En otras palabras: sí, las aguas se están calentando, pero ¿cómo varían los picos de calor y frío?

Un grupo de investigadores abordó esta pregunta estudiando los Grandes Lagos de Norteamérica, un sistema que contiene aproximadamente el 20% del agua dulce superficial del planeta y que, desde los años noventa, ha mostrado aumentos vertiginosos de temperatura, con consecuencias para ecosistemas, pesca y calidad del agua.

Para analizarlos, los científicos emplearon un modelo tridimensional similar a los usados para los océanos, adaptado a la compleja geografía del sistema lacustre. Luego aplicaron la detrendización, es decir, la eliminación de la tendencia de calentamiento a largo plazo (1940–2022), para aislar la variabilidad interna. Así permanecen solo las oscilaciones relativas, no influenciadas por el calentamiento progresivo.

Los resultados mostraron que los Grandes Lagos no solo se calientan, sino que se vuelven más variables. En comparación con los años cuarenta, el rango de variabilidad aumentó entre un 25 y un 40%, según el lago. Han crecido tanto los extremos fríos como los cálidos, con saltos marcados a partir de los años noventa, considerados verdaderos “años de ruptura” en la dinámica climática.

También crecieron los eventos extremos: las olas de calor aumentaron entre un 85% y un 258%, mientras que los períodos fríos entre un 100% y un 168%. En algunos meses de invierno y primavera, el Lago Superior registró incrementos superiores al 300%. Esto significa que hoy los lagos alternan con mayor frecuencia entre períodos excepcionalmente cálidos y fríos.

Un factor clave de esta variabilidad es la drástica reducción de la cobertura de hielo, disminuida en más del 70% en los últimos cuarenta años. El hielo funciona como una “tapa” que estabiliza las aguas: cuando falta, los lagos absorben más energía solar y se vuelven más vulnerables a las oscilaciones climáticas. A esto se suma la influencia de grandes ciclos atmosféricos globales, como El Niño o la Oscilación Ártica, que explican los puntos de inflexión observados en las series históricas.

Lamentablemente, los lagos, al tener menos agua y ser menos profundos que los océanos, no logran amortiguar las variaciones y responden de manera muy acentuada a los cambios atmosféricos. Los científicos esperan que, comprendiendo estas dinámicas, podamos prever mejor los escenarios futuros y desarrollar estrategias de gestión eficaces que preserven los ciclos naturales de los ecosistemas.

¡Hasta pronto y Buena Ciencia!

ESP version ITA version

Instagram Facebook Linktree

Science has repeatedly confirmed that the average temperature of oceans, seas, and lakes is rising as a consequence of human-driven climate change. What is less clear is how temperature extremes, both low and high, are changing. In other words, yes, waters are warming, but how are the peaks of heat and cold shifting?

A group of researchers tackled this question by studying the North American Great Lakes, a system that holds about 20% of the planet’s surface freshwater and that, since the 1990s, has experienced dramatic temperature increases with consequences for ecosystems, fisheries, and water quality.

To analyse them, scientists used a three-dimensional model similar to those employed for oceans, adapted to the complex geography of the lake system. They then applied detrending, the removal of the long-term warming trend (1940–2022), to isolate internal variability. This way, only relative oscillations remain, unaffected by progressive warming.

Results showed that the Great Lakes are not only warming but also becoming more variable. Compared to the 1940s, the range of variability has grown by 25–40%, depending on the lake. Both cold and hot extremes have increased, with particularly sharp jumps since the 1990s, considered true “break years” in climate dynamics.

Extreme events have also risen: heatwaves increased by 85–258%, while cold spells by 100–168%. In some winter and spring months, Lake Superior recorded spikes above 300%. This means that today the lakes alternate between exceptionally hot and cold periods more frequently.

A key driver of this variability is the drastic reduction of ice cover, which has shrunk by over 70% in the last forty years. Ice acts as a “lid” that stabilises waters; without it, lakes absorb more solar energy and become more vulnerable to climatic fluctuations. Added to this is the influence of major global atmospheric cycles, such as El Niño or the Arctic Oscillation, which explain turning points observed in historical series.

Unfortunately, lakes, with less water and depth than oceans, cannot buffer these variations and respond more sharply to atmospheric changes. Scientists hope that by understanding these dynamics, we will better predict future scenarios and design effective management strategies, preserving the natural cycles of ecosystems.

See You Soon, and Good Science!

ENG version ESP version

Instagram Facebook Linktree

La Scienza ha più volte confermato che la temperatura media di oceani, mari e laghi stia aumentando come conseguenza del cambiamento climatico di origine umana. È però meno chiaro come stiano cambiando gli estremi di temperatura, cioè i valori particolarmente bassi o alti. In altre parole: sì, le acque si stanno scaldando, ma in che modo stanno variando i picchi di caldo e di freddo?

Un gruppo di ricercatori ha affrontato questa domanda studiando i Grandi Laghi nordamericani, un sistema che contiene circa il 20% dell’acqua dolce superficiale del pianeta e che dagli anni ’90 ha visto aumenti vertiginosi di temperatura, con conseguenze su ecosistemi, pesca e qualità dell’acqua.

Per analizzarli, gli scienziati hanno usato un modello tridimensionale simile a quelli impiegati per gli oceani, adattato alla complessa geografia del sistema lacustre. Hanno poi applicato la detrendizzazione, ovvero la rimozione del trend di riscaldamento di lungo periodo (1940–2022), per isolare la variabilità interna. Facendo questo sono rimaste le oscillazioni relative, non influenzate dal riscaldamento progressivo.

I risultati hanno mostrato che i Grandi Laghi non solo si riscaldano, ma stanno diventando più variabili. Infatti, rispetto agli anni ’40, l’intervallo di variabilità è cresciuto dal 25 al 40% a seconda del lago. Sono aumentati sia gli estremi freddi che quelli caldi, con salti particolarmente netti dagli anni ’90 in poi, considerati veri e propri “anni di rottura” nelle dinamiche climatiche.

Anche gli eventi estremi sono cresciuti: le ondate di calore sono aumentate dall’85% al 258%, mentre i periodi freddi dal 100% al 168%. In alcuni mesi invernali e primaverili, il Lago Superiore ha visto incrementi addirittura superiori al 300%. Questo significa che oggi i laghi alternano con maggiore frequenza periodi eccezionalmente caldi e freddi.

Un ruolo chiave di questa variabilità sembra averlo la drastica riduzione della copertura di ghiaccio, diminuita di oltre il 70% negli ultimi quarant’anni. Il ghiaccio funziona come un “coperchio” che stabilizza le acque: quando manca, i laghi assorbono più energia solare e diventano più vulnerabili agli sbalzi climatici. A questo si aggiunge l’influenza dei grandi cicli atmosferici globali, come El Niño o l’Oscillazione Artica, che spiegano i punti di svolta osservati nelle serie storiche.

Purtroppo i laghi, avendo meno acqua ed essendo meno profondi, non riescono a smorzare le variazioni come succede negli oceani e rispondono in maniera molto accentuata ai cambiamenti atmosferici. Gli scienziati sperano che, conoscendo ora queste variazioni, si possano prevedere quelle future e sviluppare strategie di gestione efficaci, preservando i cicli naturali degli ecosistemi.

A Presto e Buona Scienza!